UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED

MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number 811-07139

Fidelity Hereford Street Trust

(Exact name of registrant as specified in charter)

245 Summer St., Boston, Massachusetts 02210

(Address of principal executive offices) (Zip code)

Cynthia Lo Bessette, Secretary

245 Summer St.

Boston, Massachusetts 02210

(Name and address of agent for service)

Registrant's telephone number, including area code:

617-563-7000


Date of fiscal year end:	April 30

Date of reporting period:	April 30, 2020

Item 1.

Reports to Stockholders

Fidelity® Treasury Only Money Market Fund

Annual Report

April 30, 2020

See the inside front cover for important information about access to your fund’s shareholder reports.

Fidelity Investments

Beginning on January 1, 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of a fund’s shareholder reports will no longer be sent by mail, unless you specifically request paper copies of the reports from the fund or from your financial intermediary, such as a financial advisor, broker-dealer or bank. Instead, the reports will be made available on a website, and you will be notified by mail each time a report is posted and provided with a website link to access the report.

If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive shareholder reports and other communications from a fund electronically, by contacting your financial intermediary. For Fidelity customers, visit Fidelity's web site or call Fidelity using the contact information listed below.

You may elect to receive all future reports in paper free of charge. If you wish to continue receiving paper copies of your shareholder reports, you may contact your financial intermediary or, if you are a Fidelity customer, visit Fidelity’s website, or call Fidelity at the applicable toll-free number listed below. Your election to receive reports in paper will apply to all funds held with the fund complex/your financial intermediary.

Account Type	Website	Phone Number
Brokerage, Mutual Fund, or Annuity Contracts:	fidelity.com/mailpreferences	1-800-343-3548
Employer Provided Retirement Accounts:	netbenefits.fidelity.com/preferences (choose 'no' under Required Disclosures to continue to print)	1-800-343-0860
Advisor Sold Accounts Serviced Through Your Financial Intermediary:	Contact Your Financial Intermediary	Your Financial Intermediary's phone number
Advisor Sold Accounts Serviced by Fidelity:	institutional.fidelity.com	1-877-208-0098

Contents

Note to Shareholders
Investment Summary/Performance
Schedule of Investments
Financial Statements
Notes to Financial Statements
Report of Independent Registered Public Accounting Firm
Trustees and Officers
Shareholder Expense Example
Distributions

To view a fund's proxy voting guidelines and proxy voting record for the 12-month period ended June 30, visit http://www.fidelity.com/proxyvotingresults or visit the Securities and Exchange Commission's (SEC) web site at http://www.sec.gov.

You may also call 1-800-544-8544 to request a free copy of the proxy voting guidelines.

Standard & Poor's, S&P and S&P 500 are registered service marks of The McGraw-Hill Companies, Inc. and have been licensed for use by Fidelity Distributors Corporation.

Other third-party marks appearing herein are the property of their respective owners.

This report and the financial statements contained herein are submitted for the general information of the shareholders of the Fund. This report is not authorized for distribution to prospective investors in the Fund unless preceded or accompanied by an effective prospectus.

A fund files its complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year on Form N-PORT. Forms N-PORT are available on the SEC’s web site at http://www.sec.gov. A fund's Forms N-PORT may be reviewed and copied at the SEC’s Public Reference Room in Washington, DC. Information regarding the operation of the SEC's Public Reference Room may be obtained by calling 1-800-SEC-0330.

For a complete list of a fund's portfolio holdings, view the most recent holdings listing, semiannual report, or annual report on Fidelity's web site at http://www.fidelity.com, http://www.institutional.fidelity.com, or http://www.401k.com, as applicable.

NOT FDIC INSURED •MAY LOSE VALUE •NO BANK GUARANTEE

Neither the Fund nor Fidelity Distributors Corporation is a bank.

Note to Shareholders:

Early in 2020, the outbreak and spread of a new coronavirus emerged as a public health emergency that had a major influence on financial markets, primarily based on its impact on the global economy and the outlook for corporate earnings. The virus causes a respiratory disease known as COVID-19. On March 11, the World Health Organization declared the COVID-19 outbreak a pandemic, citing sustained risk of further global spread.

In the weeks following, as the crisis worsened, we witnessed an escalating human tragedy with wide-scale social and economic consequences from coronavirus-containment measures. The outbreak of COVID-19 prompted a number of measures to limit the spread, including travel and border restrictions, quarantines, and restrictions on large gatherings. In turn, these resulted in lower consumer activity, diminished demand for a wide range of products and services, disruption in manufacturing and supply chains, and – given the wide variability in outcomes regarding the outbreak – significant market uncertainty and volatility. Amid the turmoil, the U.S. government took unprecedented action – in concert with the U.S. Federal Reserve and central banks around the world – to help support consumers, businesses, and the broader economy, and to limit disruption to the financial system.

The situation continues to unfold, and the extent and duration of its impact on financial markets and the economy remain highly uncertain. Extreme events such as the coronavirus crisis are “exogenous shocks” that can have significant adverse effects on mutual funds and their investments. Although multiple asset classes may be affected by market disruption, the duration and impact may not be the same for all types of assets.

Fidelity is committed to helping you stay informed amid news about COVID-19 and during increased market volatility, and we’re taking extra steps to be responsive to customer needs. We encourage you to visit our websites, where we offer ongoing updates, commentary, and analysis on the markets and our funds.

Investment Summary/Performance (Unaudited)

Effective Maturity Diversification as of April 30, 2020

Days	% of fund's investments 4/30/20
1 - 7	25.8
8 - 30	19.7
31 - 60	26.1
61 - 90	14.1
91 - 180	13.1
> 180	1.2

Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940.

Asset Allocation (% of fund's net assets)

As of April 30, 2020
	U.S. Treasury Debt	112.9%
	Net Other Assets (Liabilities)^*	(12.9)%

* Net Other Assets (Liabilities) are not included in the pie chart

Current 7-Day Yields

	4/30/20
Fidelity® Treasury Only Money Market Fund	0.01%

Yield refers to the income paid by the Fund over a given period. Yield for money market funds is usually for seven-day periods, as it is here, though it is expressed as an annual percentage rate. Past performance is no guarantee of future results. Yield will vary and it's possible to lose money investing in the Fund. A portion of the Fund's expenses was reimbursed and/or waived. Absent such reimbursements and/or waivers the yield for the period ending April 30, 2020,the most recent period shown in the table, would have been -0.06%.

Schedule of Investments April 30, 2020

Showing Percentage of Net Assets

U.S. Treasury Debt - 112.9%
	Yield(a)	Principal Amount (000s)	Value (000s)
U.S. Treasury Obligations - 112.9%
U.S. Treasury Bills
5/5/20 to 10/29/20	0.01 to 1.59%	$4,598,623	$4,597,368
U.S. Treasury Bonds
5/15/20 to 8/15/20	0.05 to 0.17	16,000	16,356
U.S. Treasury Notes
5/15/20 to 1/31/22	0.03 to 1.62 (b)	1,080,199	1,080,693
TOTAL U.S. TREASURY DEBT
(Cost $5,694,417)			5,694,417
TOTAL INVESTMENT IN SECURITIES - 112.9%
(Cost $5,694,417)			5,694,417
NET OTHER ASSETS (LIABILITIES) - (12.9)%			(649,078)
NET ASSETS - 100%			$5,045,339

The date shown for securities represents the date when principal payments must be paid, taking into account any call options exercised by the issuer and any permissible maturity shortening features other than interest rate resets.

Legend

(a) Yield represents either the annualized yield at the date of purchase, or the stated coupon rate, or, for floating and adjustable rate securities, the rate at period end.

(b) Coupon rates for floating and adjustable rate securities reflect the rates in effect at period end.

Investment Valuation

All investments are categorized as Level 2 under the Fair Value Hierarchy. The inputs or methodology used for valuing securities may not be an indication of the risk associated with investing in those securities. For more information on valuation inputs please refer to the Investment Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes which are an integral part of the financial statements.

Financial Statements

Statement of Assets and Liabilities

Amounts in thousands (except per-share amount)		April 30, 2020
Assets
Investment in securities, at value — See accompanying schedule: Unaffiliated issuers (cost $5,694,417)		$5,694,417
Cash		1,775
Receivable for fund shares sold		6,862
Interest receivable		2,609
Total assets		5,705,663
Liabilities
Payable for investments purchased	$612,860
Payable for fund shares redeemed	45,777
Distributions payable	12
Accrued management fee	1,675
Total liabilities		660,324
Net Assets		$5,045,339
Net Assets consist of:
Paid in capital		$5,045,327
Total accumulated earnings (loss)		12
Net Assets		$5,045,339
Net Asset Value, offering price and redemption price per share ($5,045,339 ÷ 5,044,466 shares)		$1.00

See accompanying notes which are an integral part of the financial statements.

Statement of Operations

Amounts in thousands		Year ended April 30, 2020
Investment Income
Interest		$53,519
Expenses
Management fee	$13,292
Independent trustees' fees and expenses	11
Total expenses before reductions	13,303
Expense reductions	(127)
Total expenses after reductions		13,176
Net investment income (loss)		40,343
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment securities:
Unaffiliated issuers		5
Total net realized gain (loss)		5
Net increase in net assets resulting from operations		$40,348

See accompanying notes which are an integral part of the financial statements.

Statement of Changes in Net Assets

Amounts in thousands	Year ended April 30, 2020	Year ended April 30, 2019
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$40,343	$52,766
Net realized gain (loss)	5	9
Net increase in net assets resulting from operations	40,348	52,775
Distributions to shareholders	(40,347)	(52,762)
Share transactions
Proceeds from sales of shares	4,322,438	1,262,282
Reinvestment of distributions	37,205	49,093
Cost of shares redeemed	(2,137,693)	(1,660,961)
Net increase (decrease) in net assets and shares resulting from share transactions	2,221,950	(349,586)
Total increase (decrease) in net assets	2,221,951	(349,573)
Net Assets
Beginning of period	2,823,388	3,172,961
End of period	$5,045,339	$2,823,388
Other Information
Shares
Sold	4,322,438	1,262,282
Issued in reinvestment of distributions	37,205	49,093
Redeemed	(2,137,693)	(1,660,961)
Net increase (decrease)	2,221,950	(349,586)

See accompanying notes which are an integral part of the financial statements.

Financial Highlights

Fidelity Treasury Only Money Market Fund


Years ended April 30,	2020	2019	2018	2017	2016
Selected Per–Share Data
Net asset value, beginning of period	$1.00	$1.00	$1.00	$1.00	$1.00
Income from Investment Operations
Net investment income (loss)	.014	.018	.008	–^A	–^A
Net realized and unrealized gain (loss)^A	–	–	–	–	–
Total from investment operations	.014	.018	.008	–^A	–^A
Distributions from net investment income	(.014)	(.018)	(.008)	–^A	–^A
Total distributions	(.014)	(.018)	(.008)	–^A	–^A
Net asset value, end of period	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return^B	1.39%	1.79%	.77%	.07%	.01%
Ratios to Average Net Assets^C
Expenses before reductions	.42%	.42%	.42%	.42%	.42%
Expenses net of fee waivers, if any	.42%	.42%	.42%	.38%	.16%
Expenses net of all reductions	.42%	.42%	.42%	.38%	.16%
Net investment income (loss)	1.27%	1.76%	.76%	.06%	.01%
Supplemental Data
Net assets, end of period (in millions)	$5,045	$2,823	$3,173	$3,720	$4,437

^A Amount represents less than $.0005 per share.

^B Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^C Expense ratios reflect operating expenses of the Fund. Expenses before reductions do not reflect amounts reimbursed or waived or reductions from expense offset arrangements and do not represent the amount paid by the Fund during periods when reimbursements, waivers or reductions occur. Expenses net of fee waivers reflect expenses after reimbursement and waivers but prior to reductions from expense offset arrangements. Expenses net of all reductions represent the net expenses paid by the Fund.

See accompanying notes which are an integral part of the financial statements.

Notes to Financial Statements

For the period ended April 30, 2020
(Amounts in thousands except percentages)

1. Organization.

Fidelity Treasury Only Money Market Fund (the Fund) is a fund of Fidelity Hereford Street Trust (the Trust) and is authorized to issue an unlimited number of shares. Share transactions on the Statement of Changes in Net Assets may contain exchanges between affiliated funds. The Trust is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company organized as a Delaware statutory trust. Effective after the close of business on March 31, 2020, the Fund is closed to new accounts with certain exceptions.

Effective January 1, 2020:

Investment advisers Fidelity Investments Money Management, Inc., FMR Co., Inc., and Fidelity SelectCo, LLC, merged with and into Fidelity Management & Research Company. In connection with the merger transactions, the resulting, merged investment adviser was then redomiciled from Massachusetts to Delaware, changed its corporate structure from a corporation to a limited liability company, and changed its name to "Fidelity Management & Research Company LLC".

2. Significant Accounting Policies.

The Fund is an investment company and applies the accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services – Investments Companies. The financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP), which require management to make certain estimates and assumptions at the date of the financial statements. Actual results could differ from those estimates. Subsequent events, if any, through the date that the financial statements were issued have been evaluated in the preparation of the financial statements. The following summarizes the significant accounting policies of the Fund:

Investment Valuation. The Fund categorizes the inputs to valuation techniques used to value its investments into a disclosure hierarchy consisting of three levels as shown below:

Level 1 – quoted prices in active markets for identical investments
Level 2 – other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, etc.)
Level 3 – unobservable inputs (including the Fund's own assumptions based on the best information available)

As permitted by compliance with certain conditions under Rule 2a-7 of the 1940 Act, securities are valued at amortized cost, which approximates fair value. The amortized cost of an instrument is determined by valuing it at its original cost and thereafter amortizing any discount or premium from its face value at a constant rate until maturity. Securities held by a money market fund are generally high quality and liquid; however, they are reflected as Level 2 because the inputs used to determine fair value are not quoted prices in an active market.

Investment Transactions and Income. The net asset value per share for processing shareholder transactions is calculated as of the close of business of the New York Stock Exchange (NYSE), normally 4:00 p.m. Eastern time. Security transactions are accounted for as of trade date. Gains and losses on securities sold are determined on the basis of identified cost and include proceeds received from litigation. Interest income is accrued as earned and includes coupon interest and amortization of premium and accretion of discount on debt securities as applicable.

Expenses. Expenses directly attributable to a fund are charged to that fund. Expenses attributable to more than one fund are allocated among the respective funds on the basis of relative net assets or other appropriate methods. Expense estimates are accrued in the period to which they relate and adjustments are made when actual amounts are known.

Income Tax Information and Distributions to Shareholders. Each year, the Fund intends to qualify as a regulated investment company under Subchapter M of the Internal Revenue Code, including distributing substantially all of its taxable income and realized gains. As a result, no provision for U.S. Federal income taxes is required. As of April 30, 2020, the Fund did not have any unrecognized tax benefits in the financial statements; nor is the Fund aware of any tax positions for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. The Fund files a U.S. federal tax return, in addition to state and local tax returns as required. The Fund's federal income tax returns are subject to examination by the Internal Revenue Service (IRS) for a period of three fiscal years after they are filed. State and local tax returns may be subject to examination for an additional fiscal year depending on the jurisdiction.

Distributions are declared and recorded daily and paid monthly from net investment income. Distributions from realized gains, if any, are declared and recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from GAAP. In addition, the Fund claimed a portion of the payment made to redeeming shareholders as a distribution for income tax purposes.

Capital accounts within the financial statements are adjusted for permanent book-tax differences. These adjustments have no impact on net assets or the results of operations. Capital accounts are not adjusted for temporary book-tax differences which will reverse in a subsequent period.

Book-tax differences are primarily due to losses deferred due to wash sales.

As of period end, the cost and unrealized appreciation (depreciation) in securities for federal income tax purposes were as follows:

Gross unrealized appreciation	$–
Gross unrealized depreciation	–
Net unrealized appreciation (depreciation)	$–
Tax Cost	$5,694,417

The tax-based components of distributable earnings as of period end were as follows:

Undistributed ordinary income

$94

The tax character of distributions paid was as follows:

	April 30, 2020	April 30, 2019
Ordinary Income	$40,347	$ 52,762

3. Fees and Other Transactions with Affiliates.

Management Fee. Fidelity Management & Research Company LLC (the investment adviser) and its affiliates provide the Fund with investment management related services for which the Fund pays a monthly management fee that is based on an annual rate of .42% of the Fund's average net assets. Under the management contract, the investment adviser pays all other expenses, except the compensation of the independent Trustees and certain other expenses such as interest expense. The management fee is reduced by an amount equal to the fees and expenses paid by the Fund to the independent Trustees.

Interfund Trades. Funds may purchase from or sell securities to other Fidelity Funds under procedures adopted by the Board. The procedures have been designed to ensure these interfund trades are executed in accordance with Rule 17a-7 of the 1940 Act.

4. Expense Reductions.

The investment adviser or its affiliates voluntarily agreed to waive certain fees in order to avoid a negative yield. Such arrangements may be discontinued by the investment adviser at any time. For the period, the amount of the waiver was $123.

In addition, through arrangements with the Fund's custodian and transfer agent, credits realized as a result of certain uninvested cash balances were used to reduce the Fund's expenses by $4 and less than five hundred dollars, respectively.

5. Other.

The Fund's organizational documents provide former and current trustees and officers with a limited indemnification against liabilities arising in connection with the performance of their duties to the Fund. In the normal course of business, the Fund may also enter into contracts that provide general indemnifications. The Fund's maximum exposure under these arrangements is unknown as this would be dependent on future claims that may be made against the Fund. The risk of material loss from such claims is considered remote.

6. Coronavirus (COVID-19) Pandemic.

An outbreak of COVID-19 first detected in China during December 2019 has since spread globally and was declared a pandemic by the World Health Organization during March 2020. Developments that disrupt global economies and financial markets, such as the COVID-19 pandemic, may magnify factors that affect the Fund's performance.

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of Fidelity Hereford Street Trust and Shareholders of Fidelity Treasury Only Money Market Fund

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Fidelity Treasury Only Money Market Fund (one of the funds constituting Fidelity Hereford Street Trust, referred to hereafter as the “Fund”) as of April 30, 2020, the related statement of operations for the year ended April 30, 2020, the statement of changes in net assets for each of the two years in the period ended April 30, 2020, including the related notes, and the financial highlights for each of the five years in the period ended April 30, 2020 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Fund as of April 30, 2020, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended April 30, 2020 and the financial highlights for each of the five years in the period ended April 30, 2020 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Fund’s management. Our responsibility is to express an opinion on the Fund’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Fund in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits of these financial statements in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of April 30, 2020 by correspondence with the custodian and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

PricewaterhouseCoopers LLP

Boston, Massachusetts

June 10, 2020

We have served as the auditor of one or more investment companies in the Fidelity group of funds since 1932.

Trustees and Officers

The Trustees, Members of the Advisory Board (if any), and officers of the trust and fund, as applicable, are listed below. The Board of Trustees governs the fund and is responsible for protecting the interests of shareholders. The Trustees are experienced executives who meet periodically throughout the year to oversee the fund's activities, review contractual arrangements with companies that provide services to the fund, oversee management of the risks associated with such activities and contractual arrangements, and review the fund's performance. Each of the Trustees oversees 282 funds.

The Trustees hold office without limit in time except that (a) any Trustee may resign; (b) any Trustee may be removed by written instrument, signed by at least two-thirds of the number of Trustees prior to such removal; (c) any Trustee who requests to be retired or who has become incapacitated by illness or injury may be retired by written instrument signed by a majority of the other Trustees; and (d) any Trustee may be removed at any special meeting of shareholders by a two-thirds vote of the outstanding voting securities of the trust. Each Trustee who is not an interested person (as defined in the 1940 Act) of the trust and the fund is referred to herein as an Independent Trustee. Each Independent Trustee shall retire not later than the last day of the calendar year in which his or her 75th birthday occurs. The Independent Trustees may waive this mandatory retirement age policy with respect to individual Trustees. Officers and Advisory Board Members hold office without limit in time, except that any officer or Advisory Board Member may resign or may be removed by a vote of a majority of the Trustees at any regular meeting or any special meeting of the Trustees. Except as indicated, each individual has held the office shown or other offices in the same company for the past five years.

The fund’s Statement of Additional Information (SAI) includes more information about the Trustees. To request a free copy, call Fidelity at 1-800-544-8544.

Experience, Skills, Attributes, and Qualifications of the Trustees. The Governance and Nominating Committee has adopted a statement of policy that describes the experience, qualifications, attributes, and skills that are necessary and desirable for potential Independent Trustee candidates (Statement of Policy). The Board believes that each Trustee satisfied at the time he or she was initially elected or appointed a Trustee, and continues to satisfy, the standards contemplated by the Statement of Policy. The Governance and Nominating Committee also engages professional search firms to help identify potential Independent Trustee candidates who have the experience, qualifications, attributes, and skills consistent with the Statement of Policy. From time to time, additional criteria based on the composition and skills of the current Independent Trustees, as well as experience or skills that may be appropriate in light of future changes to board composition, business conditions, and regulatory or other developments, have also been considered by the professional search firms and the Governance and Nominating Committee. In addition, the Board takes into account the Trustees' commitment and participation in Board and committee meetings, as well as their leadership of standing and ad hoc committees throughout their tenure.

In determining that a particular Trustee was and continues to be qualified to serve as a Trustee, the Board has considered a variety of criteria, none of which, in isolation, was controlling. The Board believes that, collectively, the Trustees have balanced and diverse experience, qualifications, attributes, and skills, which allow the Board to operate effectively in governing the fund and protecting the interests of shareholders. Information about the specific experience, skills, attributes, and qualifications of each Trustee, which in each case led to the Board's conclusion that the Trustee should serve (or continue to serve) as a trustee of the fund, is provided below.

Board Structure and Oversight Function. Abigail P. Johnson is an interested person and currently serves as Chairman. The Trustees have determined that an interested Chairman is appropriate and benefits shareholders because an interested Chairman has a personal and professional stake in the quality and continuity of services provided to the fund. Independent Trustees exercise their informed business judgment to appoint an individual of their choosing to serve as Chairman, regardless of whether the Trustee happens to be independent or a member of management. The Independent Trustees have determined that they can act independently and effectively without having an Independent Trustee serve as Chairman and that a key structural component for assuring that they are in a position to do so is for the Independent Trustees to constitute a substantial majority for the Board. The Independent Trustees also regularly meet in executive session. Arthur E. Johnson serves as Chairman of the Independent Trustees and as such (i) acts as a liaison between the Independent Trustees and management with respect to matters important to the Independent Trustees and (ii) with management prepares agendas for Board meetings.

Fidelity^® funds are overseen by different Boards of Trustees. The fund's Board oversees Fidelity's investment-grade bond, money market, asset allocation and certain equity funds, and other Boards oversee Fidelity's high income and other equity funds. The asset allocation funds may invest in Fidelity^® funds that are overseen by such other Boards. The use of separate Boards, each with its own committee structure, allows the Trustees of each group of Fidelity^® funds to focus on the unique issues of the funds they oversee, including common research, investment, and operational issues. On occasion, the separate Boards establish joint committees to address issues of overlapping consequences for the Fidelity^® funds overseen by each Board.

The Trustees operate using a system of committees to facilitate the timely and efficient consideration of all matters of importance to the Trustees, the fund, and fund shareholders and to facilitate compliance with legal and regulatory requirements and oversight of the fund's activities and associated risks. The Board, acting through its committees, has charged FMR and its affiliates with (i) identifying events or circumstances the occurrence of which could have demonstrably adverse effects on the fund's business and/or reputation; (ii) implementing processes and controls to lessen the possibility that such events or circumstances occur or to mitigate the effects of such events or circumstances if they do occur; and (iii) creating and maintaining a system designed to evaluate continuously business and market conditions in order to facilitate the identification and implementation processes described in (i) and (ii) above. Because the day-to-day operations and activities of the fund are carried out by or through FMR, its affiliates, and other service providers, the fund's exposure to risks is mitigated but not eliminated by the processes overseen by the Trustees. While each of the Board's committees has responsibility for overseeing different aspects of the fund's activities, oversight is exercised primarily through the Operations and Audit Committees. In addition, an ad hoc Board committee of Independent Trustees has worked with FMR to enhance the Board's oversight of investment and financial risks, legal and regulatory risks, technology risks, and operational risks, including the development of additional risk reporting to the Board. The Operations Committee also worked and continues to work with FMR to enhance the stress tests required under SEC regulations for money market funds. Appropriate personnel, including but not limited to the fund's Chief Compliance Officer (CCO), FMR's internal auditor, the independent accountants, the fund's Treasurer and portfolio management personnel, make periodic reports to the Board's committees, as appropriate, including an annual review of Fidelity's risk management program for the Fidelity^® funds. The responsibilities of each standing committee, including their oversight responsibilities, are described further under "Standing Committees of the Trustees."

Interested Trustees*:

Correspondence intended for a Trustee who is an interested person may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Abigail P. Johnson (1961)

Year of Election or Appointment: 2009

Trustee

Chairman of the Board of Trustees

Ms. Johnson also serves as Trustee of other Fidelity^® funds. Ms. Johnson serves as Chairman (2016-present), Chief Executive Officer (2014-present), and Director (2007-present) of FMR LLC (diversified financial services company), President of Fidelity Financial Services (2012-present) and President of Personal, Workplace and Institutional Services (2005-present). Ms. Johnson is Chairman and Director of Fidelity Management & Research Company LLC (investment adviser firm, 2011-present). Previously, Ms. Johnson served as Chairman and Director of FMR Co., Inc. (investment adviser firm, 2011-2019), Vice Chairman (2007-2016) and President (2013-2016) of FMR LLC, President and a Director of Fidelity Management & Research Company (2001-2005), a Trustee of other investment companies advised by Fidelity Management & Research Company, Fidelity Investments Money Management, Inc. (investment adviser firm), and FMR Co., Inc. (2001-2005), Senior Vice President of the Fidelity^® funds (2001-2005), and managed a number of Fidelity^® funds. Ms. Abigail P. Johnson and Mr. Arthur E. Johnson are not related.

Jennifer Toolin McAuliffe (1959)

Year of Election or Appointment: 2016

Trustee

Ms. McAuliffe also serves as Trustee of other Fidelity^® funds. Previously, Ms. McAuliffe served as Co-Head of Fixed Income of Fidelity Investments Limited (now known as FIL Limited (FIL)) (diversified financial services company), Director of Research for FIL’s credit and quantitative teams in London, Hong Kong and Tokyo and Director of Research for taxable and municipal bonds at Fidelity Investments Money Management, Inc. Ms. McAuliffe previously served as a member of the Advisory Board of certain Fidelity^® funds (2016). Ms. McAuliffe was previously a lawyer at Ropes & Gray LLP and currently serves as director or trustee of several not-for-profit entities.

* Determined to be an “Interested Trustee” by virtue of, among other things, his or her affiliation with the trust or various entities under common control with FMR.

+ The information includes the Trustee's principal occupation during the last five years and other information relating to the experience, attributes, and skills relevant to the Trustee's qualifications to serve as a Trustee, which led to the conclusion that the Trustee should serve as a Trustee for the fund.

Independent Trustees:

Correspondence intended for an Independent Trustee may be sent to Fidelity Investments, P.O. Box 55235, Boston, Massachusetts 02205-5235.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Elizabeth S. Acton (1951)

Year of Election or Appointment: 2013

Trustee

Ms. Acton also serves as Trustee of other Fidelity^® funds. Prior to her retirement, Ms. Acton served as Executive Vice President, Finance (2011-2012), Executive Vice President, Chief Financial Officer (2002-2011) and Treasurer (2004-2005) of Comerica Incorporated (financial services). Prior to joining Comerica, Ms. Acton held a variety of positions at Ford Motor Company (1983-2002), including Vice President and Treasurer (2000-2002) and Executive Vice President and Chief Financial Officer of Ford Motor Credit Company (1998-2000). Ms. Acton currently serves as a member of the Board and Audit and Finance Committees of Beazer Homes USA, Inc. (homebuilding, 2012-present). Ms. Acton previously served as a member of the Advisory Board of certain Fidelity^® funds (2013-2016).

Ann E. Dunwoody (1953)

Year of Election or Appointment: 2018

Trustee

General Dunwoody also serves as Trustee of other Fidelity^® funds. General Dunwoody (United States Army, Retired) was the first woman in U.S. military history to achieve the rank of four-star general and prior to her retirement in 2012 held a variety of positions within the U.S. Army, including Commanding General, U.S. Army Material Command (2008-2012). General Dunwoody currently serves as President of First to Four LLC (leadership and mentoring services, 2012-present), a member of the Board and Nomination and Corporate Governance Committees of Kforce Inc. (professional staffing services, 2016-present) and a member of the Board of Automattic Inc. (software engineering, 2018-present). Previously, General Dunwoody served as a member of the Advisory Board and Nominating and Corporate Governance Committee of L3 Technologies, Inc. (communication, electronic, sensor and aerospace systems, 2013-2019) and a member of the Board and Audit and Sustainability and Corporate Responsibility Committees of Republic Services, Inc. (waste collection, disposal and recycling, 2013-2016). Ms. Dunwoody also serves on several boards for non-profit organizations, including as a member of the Board, Chair of the Nomination and Governance Committee and a member of the Audit Committee of Logistics Management Institute (consulting non-profit, 2012-present), a member of the Council of Trustees for the Association of the United States Army (advocacy non-profit, 2013-present), a member of the Board of Florida Institute of Technology (2015-present) and a member of the Board of ThanksUSA (military family education non-profit, 2014-present). General Dunwoody previously served as a member of the Advisory Board of certain Fidelity^® funds (2018).

John Engler (1948)

Year of Election or Appointment: 2014

Trustee

Mr. Engler also serves as Trustee of other Fidelity^® funds. Previously, Mr. Engler served as Governor of Michigan (1991-2003), President of the Business Roundtable (2011-2017) and interim President of Michigan State University (2018-2019). Mr. Engler currently serves as a member of the Board of K12 Inc. (technology-based education company, 2012-present). Previously, Mr. Engler served as a member of the Board of Universal Forest Products (manufacturer and distributor of wood and wood-alternative products, 2003-2019) and Trustee of The Munder Funds (2003-2014). Mr. Engler previously served as a member of the Advisory Board of certain Fidelity^® funds (2014-2016).

Robert F. Gartland (1951)

Year of Election or Appointment: 2010

Trustee

Mr. Gartland also serves as Trustee of other Fidelity^® funds. Prior to his retirement, Mr. Gartland held a variety of positions at Morgan Stanley (financial services, 1979-2007), including Managing Director (1987-2007) and Chase Manhattan Bank (1975-1978). Mr. Gartland previously served as Chairman and an investor in Gartland & Mellina Group Corp. (consulting, 2009-2019), as a member of the Board of National Securities Clearing Corporation (1993-1996) and as Chairman of TradeWeb (2003-2004).

Arthur E. Johnson (1947)

Year of Election or Appointment: 2008

Trustee

Chairman of the Independent Trustees

Mr. Johnson also serves as Trustee of other Fidelity^® funds. Prior to his retirement, Mr. Johnson served as Senior Vice President of Corporate Strategic Development of Lockheed Martin Corporation (defense contractor, 1999-2009). Mr. Johnson currently serves as a member of the Board of Booz Allen Hamilton (management consulting, 2011-present). Mr. Johnson previously served as a member of the Board of Eaton Corporation plc (diversified power management, 2009-2019) and a member of the Board of AGL Resources, Inc. (holding company, 2002-2016). Mr. Johnson previously served as Vice Chairman (2015-2018) of the Independent Trustees of certain Fidelity^® funds. Mr. Arthur E. Johnson is not related to Ms. Abigail P. Johnson.

Michael E. Kenneally (1954)

Year of Election or Appointment: 2009

Trustee

Vice Chairman of the Independent Trustees

Mr. Kenneally also serves as Trustee of other Fidelity^® funds. Prior to his retirement, Mr. Kenneally served as Chairman and Global Chief Executive Officer of Credit Suisse Asset Management and Executive Vice President and Chief Investment Officer of Bank of America Corporation. Earlier roles at Bank of America included Director of Research, Senior Portfolio Manager for various institutional equity accounts and mutual funds and Portfolio Manager for a number of institutional fixed-income clients. Mr. Kenneally began his career as a Research Analyst in 1983 and was awarded the Chartered Financial Analyst (CFA) designation in 1991.

Marie L. Knowles (1946)

Year of Election or Appointment: 2001

Trustee

Ms. Knowles also serves as Trustee of other Fidelity^® funds. Prior to her retirement, Ms. Knowles held several positions at Atlantic Richfield Company (diversified energy), including Executive Vice President and Chief Financial Officer (1996-2000), Senior Vice President (1993-1996) and President of ARCO Transportation Company (pipeline and tanker operations, 1993-1996). Ms. Knowles currently serves as a member of the Board of McKesson Corporation (healthcare service, since 2002), a member of the Board of the Santa Catalina Island Company (real estate, 2009-present), a member of the Investment Company Institute Board of Governors and a member of the Governing Council of the Independent Directors Council (2014-present). Ms. Knowles also serves as a member of the Advisory Board for the School of Engineering of the University of Southern California. Ms. Knowles previously served as Chairman (2015-2018) and Vice Chairman (2012-2015) of the Independent Trustees of certain Fidelity^® funds.

Mark A. Murray (1954)

Year of Election or Appointment: 2016

Trustee

Mr. Murray also serves as Trustee of other Fidelity^® funds. Previously, Mr. Murray served as Co-Chief Executive Officer (2013-2016), President (2006-2013) and Vice Chairman (2013-2020) of Meijer, Inc. Mr. Murray serves as a member of the Board and Nuclear Review and Public Policy and Responsibility Committees of DTE Energy Company (diversified energy company, 2009-present) and a member of the Board and Audit Committee and Chairman of the Nominating and Corporate Governance Committee of Universal Forest Products, Inc. (manufacturer and distributor of wood and wood-alternative products, 2004-2016). Mr. Murray previously served as a member of the Board of Spectrum Health (not-for-profit health system, 2015-2019). Mr. Murray also serves as a member of the Board of many community and professional organizations. Mr. Murray previously served as a member of the Advisory Board of certain Fidelity^® funds (2016).

Advisory Board Members and Officers:

Correspondence intended for an officer may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210. Officers appear below in alphabetical order.

Name, Year of Birth; Principal Occupation

Elizabeth Paige Baumann (1968)

Year of Election or Appointment: 2017

Anti-Money Laundering (AML) Officer

Ms. Baumann also serves as AML Officer of other funds. She is Chief AML Officer (2012-present) and Senior Vice President (2014-present) of FMR LLC (diversified financial services company) and is an employee of Fidelity Investments. Previously, Ms. Baumann served as AML Officer of certain funds (2017-2019), as AML Officer of the funds (2012-2016), and Vice President (2007-2014) and Deputy Anti-Money Laundering Officer (2007-2012) of FMR LLC.

Craig S. Brown (1977)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Brown also serves as Assistant Treasurer of other funds. Mr. Brown is an employee of Fidelity Investments (2013-present).

John J. Burke III (1964)

Year of Election or Appointment: 2018

Chief Financial Officer

Mr. Burke also serves as Chief Financial Officer of other funds. Mr. Burke serves as Head of Investment Operations for Fidelity Fund and Investment Operations (2018-present) and is an employee of Fidelity Investments (1998-present). Previously Mr. Burke served as head of Asset Management Investment Operations (2012-2018).

David J. Carter (1973)

Year of Election or Appointment: 2020

Assistant Secretary

Mr. Carter also serves as Assistant Secretary of other funds. Mr. Carter serves as Vice President, Associate General Counsel (2010-present) and is an employee of Fidelity Investments (2005-present).

Jonathan Davis (1968)

Year of Election or Appointment: 2010

Assistant Treasurer

Mr. Davis also serves as Assistant Treasurer of other funds. Mr. Davis serves as Assistant Treasurer of FMR Capital, Inc. (2017-present) and is an employee of Fidelity Investments. Previously, Mr. Davis served as Vice President and Associate General Counsel of FMR LLC (diversified financial services company, 2003-2010).

Laura M. Del Prato (1964)

Year of Election or Appointment: 2018

President and Treasurer

Ms. Del Prato also serves as an officer of other funds. Ms. Del Prato is an employee of Fidelity Investments (2017-present). Prior to joining Fidelity Investments, Ms. Del Prato served as a Managing Director and Treasurer of the JPMorgan Mutual Funds (2014-2017). Prior to JPMorgan, Ms. Del Prato served as a partner at Cohen Fund Audit Services (accounting firm, 2012-2013) and KPMG LLP (accounting firm, 2004-2012).

Colm A. Hogan (1973)

Year of Election or Appointment: 2016

Assistant Treasurer

Mr. Hogan also serves as an officer of other funds. Mr. Hogan serves as Assistant Treasurer of FMR Capital, Inc. (2017-present) and is an employee of Fidelity Investments (2005-present). Previously, Mr. Hogan served as Deputy Treasurer of certain Fidelity^® funds (2016-2020) and Assistant Treasurer of certain Fidelity^® funds (2016-2018).

Cynthia Lo Bessette (1969)

Year of Election or Appointment: 2019

Secretary and Chief Legal Officer (CLO)

Ms. Lo Bessette also serves as an officer of other funds. Ms. Lo Bessette serves as CLO, Secretary, and Senior Vice President of Fidelity Management & Research Company LLC (investment adviser firm, 2019-present); and CLO of Fidelity Management & Research (Hong Kong) Limited, FMR Investment Management (UK) Limited, and Fidelity Management & Research (Japan) Limited (investment adviser firms, 2019-present). She is a Senior Vice President and Deputy General Counsel of FMR LLC (diversified financial services company, 2019-present), and is an employee of Fidelity Investments. Previously, Ms. Lo Bessette served as CLO, Secretary, and Senior Vice President of FMR Co., Inc. (investment adviser firm, 2019); Secretary of Fidelity SelectCo, LLC and Fidelity Investments Money Management, Inc. (investment adviser firms, 2019). Prior to joining Fidelity Investments, Ms. Lo Bessette was Executive Vice President, General Counsel (2016-2019) and Senior Vice President, Deputy General Counsel (2015-2016) of OppenheimerFunds (investment management company) and Deputy Chief Legal Officer (2013-2015) of Jennison Associates LLC (investment adviser firm).

Chris Maher (1972)

Year of Election or Appointment: 2013

Assistant Treasurer

Mr. Maher also serves as an officer of other funds. Mr. Maher serves as Assistant Treasurer of FMR Capital, Inc. (2017-present), and is an employee of Fidelity Investments (2008-present). Previously, Mr. Maher served as Assistant Treasurer of certain funds (2013-2020); Vice President of Asset Management Compliance (2013), Vice President of the Program Management Group of FMR (investment adviser firm, 2010-2013), and Vice President of Valuation Oversight (2008-2010).

Nancy D. Prior (1967)

Year of Election or Appointment: 2014

Vice President

Ms. Prior also serves as Vice President of other funds. Ms. Prior serves as President of Fixed Income (2014-present), and is an employee of Fidelity Investments (2002-present). Previously, Ms. Prior served as President (2016-2019) and Director (2014-2019) of Fidelity Investments Money Management, Inc. (FIMM) (investment adviser firm), Vice President of Global Asset Allocation Funds (2017-2019); Vice Chairman of FIAM LLC (investment adviser firm, 2014-2018), a Director of FMR Investment Management (UK) Limited (investment adviser firm, 2015-2018), President Multi-Asset Class Strategies of FMR's Global Asset Allocation Division (2017-2018), Vice President of Fidelity's Money Market Funds (2012-2014), and President, Money Market and Short Duration Bond Group of Fidelity Management & Research Company (FMR) (investment adviser firm, 2013-2014).

Kenneth B. Robins (1969)

Year of Election or Appointment: 2020

Chief Compliance Officer

Mr. Robins also serves as an officer of other funds. Mr. Robins serves as Compliance Officer of Fidelity Management & Research Company LLC (investment adviser firm, 2016-present) and is an employee of Fidelity Investments (2004-present). Previously, Mr. Robins served as Compliance Officer of FMR Co., Inc. (investment adviser firm, 2016-2019), as Executive Vice President of Fidelity Investments Money Management, Inc. (investment adviser firm, 2013-2016) and served in other fund officer roles.

Stacie M. Smith (1974)

Year of Election or Appointment: 2013

Assistant Treasurer

Ms. Smith also serves as an officer of other funds. Ms. Smith serves as Assistant Treasurer of FMR Capital, Inc. (2017-present), is an employee of Fidelity Investments (2009-present), and has served in other fund officer roles. Prior to joining Fidelity Investments, Ms. Smith served as Senior Audit Manager of Ernst & Young LLP (accounting firm, 1996-2009). Previously, Ms. Smith served as Assistant Treasurer (2013-2019) and Deputy Treasurer (2013-2016) of certain Fidelity^® funds.

Marc L. Spector (1972)

Year of Election or Appointment: 2016

Deputy Treasurer

Mr. Spector also serves as an officer of other funds. Mr. Spector serves as Assistant Treasurer of FMR Capital, Inc. (2017-present) and is an employee of Fidelity Investments (2016-present). Prior to joining Fidelity Investments, Mr. Spector served as Director at the Siegfried Group (accounting firm, 2013-2016), and prior to Siegfried Group as audit senior manager at Deloitte & Touche LLP (accounting firm, 2005-2013).

Jim Wegmann (1979)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Wegmann also serves as Assistant Treasurer of other funds. Mr. Wegmann is an employee of Fidelity Investments (2011-present).

Shareholder Expense Example

As a shareholder of the Fund, you incur two types of costs: (1) transaction costs and (2) ongoing costs, including management fees and other Fund expenses. This Example is intended to help you understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds.

The Example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period (November 1, 2019 to April 30, 2020).

Actual Expenses

Hypothetical Example for Comparison Purposes

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transaction costs. Therefore, the second line of the table is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds.

	Annualized Expense Ratio-^A	Beginning Account Value November 1, 2019	Ending Account Value April 30, 2020	Expenses Paid During Period-^B November 1, 2019 to April 30, 2020
Actual	.42%	$1,000.00	$1,004.80	$2.09
Hypothetical-^C		$1,000.00	$1,022.77	$2.11

^A Annualized expense ratio reflects expenses net of applicable fee waivers.

^B Expenses are equal to the Fund's annualized expense ratio, multiplied by the average account value over the period, multiplied by 182/366 (to reflect the one-half year period).

^C 5% return per year before expenses

Distributions (Unaudited)

A total of 100% of the dividends distributed during the fiscal year was derived from interest on U.S. Government securities which is generally exempt from state income tax.

The fund designates $7,696,982 of distributions paid during the period January 1, 2020 to April 30, 2020 as qualifying to be taxed as interest-related dividends for nonresident alien shareholders.

The fund will notify shareholders in January 2021 of amounts for use in preparing 2020 income tax returns.

Fidelity Investments

TMM-ANN-0620
1.703531.122

Fidelity® Money Market Fund

Annual Report

April 30, 2020

See the inside front cover for important information about access to your fund’s shareholder reports.

Fidelity Investments

Account Type	Website	Phone Number
Brokerage, Mutual Fund, or Annuity Contracts:	fidelity.com/mailpreferences	1-800-343-3548
Employer Provided Retirement Accounts:	netbenefits.fidelity.com/preferences (choose 'no' under Required Disclosures to continue to print)	1-800-343-0860
Advisor Sold Accounts Serviced Through Your Financial Intermediary:	Contact Your Financial Intermediary	Your Financial Intermediary's phone number
Advisor Sold Accounts Serviced by Fidelity:	institutional.fidelity.com	1-877-208-0098

Contents

Note to Shareholders
Investment Summary/Performance
Schedule of Investments
Financial Statements
Notes to Financial Statements
Report of Independent Registered Public Accounting Firm
Trustees and Officers
Shareholder Expense Example
Distributions

You may also call 1-800-544-8544 to request a free copy of the proxy voting guidelines.

Standard & Poor's, S&P and S&P 500 are registered service marks of The McGraw-Hill Companies, Inc. and have been licensed for use by Fidelity Distributors Corporation.

Other third-party marks appearing herein are the property of their respective owners.

NOT FDIC INSURED •MAY LOSE VALUE •NO BANK GUARANTEE

Neither the Fund nor Fidelity Distributors Corporation is a bank.

Note to Shareholders:

Investment Summary/Performance (Unaudited)

Effective Maturity Diversification

Days	% of fund's investments 4/30/20
1 - 7	30.6
8 - 30	22.9
31 - 60	13.5
61 - 90	14.5
91 - 180	18.5

Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940.

Asset Allocation (% of fund's net assets)

As of April 30, 2020
	Certificates of Deposit	32.5%
	Commercial Paper	17.2%
	Variable Rate Demand Notes (VRDNs)	0.4%
	U.S. Treasury Debt	25.4%
	Non-Negotiable Time Deposit	5.7%
	Other Instruments	0.3%
	Interfund Loans	0.1%
	Repurchase Agreements	20.2%
	Net Other Assets (Liabilities)^*	(1.8)%

* Short-Term Investments and Net Other Assets (Liabilities) are not included in the pie chart

Current 7-Day Yields

	4/30/20
Fidelity® Money Market Fund	0.31%
Premium Class	0.43%

Yield refers to the income paid by the Fund over a given period. Yield for money market funds is usually for seven-day periods, as it is here, though it is expressed as an annual percentage rate. Past performance is no guarantee of future results. Yield will vary and it's possible to lose money investing in the Fund. A portion of the Fund's expenses was reimbursed and/or waived. Absent such reimbursements and/or waivers the yield for the period ending April 30, 2020, the most recent period shown in the table, would have been .36% for Premium Class.

Schedule of Investments April 30, 2020

Showing Percentage of Net Assets

Certificate of Deposit - 32.5%
	Yield(a)	Principal Amount (000s)	Value (000s)
Domestic Certificates Of Deposit - 0.2%
Wells Fargo Bank NA
7/27/20	0.59 (b)(c)%	$122,000	$122,000
London Branch, Eurodollar, Foreign Banks - 8.2%
Bank of Montreal London Branch
7/20/20	1.54	87,000	87,000
Credit Agricole SA London Branch
5/4/20 to 7/3/20	1.48 to 1.79	438,000	438,000
DZ Bank AG London Branch
5/13/20 to 6/22/20	1.66 to 1.79	1,446,000	1,444,164
KBC Bank NV London
5/18/20 to 6/29/20	1.61 to 1.76	1,235,000	1,233,589
Mitsubishi UFJ Trust & Banking Corp.
5/20/20	1.69	70,000	69,938
Mizuho Bank Ltd. London Branch
5/5/20 to 6/2/20	1.62 to 1.73	559,000	558,472
Rabobank Nederland London Branch
6/19/20 to 6/22/20	1.66 to 1.66	349,000	348,193
Sumitomo Mitsui Trust Bank Ltd. London Branch
5/7/20 to 5/29/20	1.74 to 1.82	302,000	301,765
			4,481,121
New York Branch, Yankee Dollar, Foreign Banks - 24.1%
Bank of Montreal
8/24/20 to 11/17/20	0.85 to 1.77 (b)	1,466,600	1,466,600
Bank of Nova Scotia
8/20/20 to 9/3/20	1.55 to 1.78 (b)(c)	499,000	499,000
Bank of Tokyo-Mitsubishi UFJ Ltd.
6/30/20 to 7/23/20	1.00 to 1.60	1,449,000	1,449,000
Barclays Bank PLC
5/4/20 to 8/13/20	0.57 to 1.75	1,104,650	1,104,650
Credit Suisse AG
7/7/20	1.30	535,000	535,000
Mitsubishi UFJ Trust & Banking Corp.
5/13/20 to 7/7/20	0.77 to 1.46 (b)	789,000	789,000
Mizuho Corporate Bank Ltd.
5/13/20 to 7/1/20	0.89 to 1.46 (b)	1,016,600	1,016,600
Natexis Banques Populaires New York Branch
6/5/20 to 7/24/20	0.67 to 1.06	1,695,000	1,695,000
Royal Bank of Canada
8/27/20 to 9/10/20	0.98 to 1.72 (b)(c)	495,650	495,650
Sumitomo Mitsui Banking Corp.
5/8/20 to 8/10/20	0.50 to 1.12 (b)	1,986,000	1,986,000
Sumitomo Mitsui Trust Bank Ltd.
5/11/20 to 8/11/20	0.49 to 1.03 (b)	1,823,000	1,823,000
Svenska Handelsbanken, Inc.
8/11/20	0.88 (b)(c)	333,000	333,000
			13,192,500
TOTAL CERTIFICATE OF DEPOSIT
(Cost $17,795,621)			17,795,621

Financial Company Commercial Paper - 16.9%
Bank of Nova Scotia
7/15/20 to 11/13/20	0.85 to 1.78 (b)(c)	1,293,000	1,293,000
Barclays Bank PLC/Barclays U.S. CCP Funding LLC
5/1/20	1.66 (d)	67,000	67,000
BPCE SA
6/24/20	1.61	120,000	119,712
Canadian Imperial Bank of Commerce
7/15/20 to 9/14/20	0.85 to 1.09 (b)	1,381,000	1,378,921
Citigroup Global Markets, Inc.
7/22/20 to 8/5/20	0.86 to 1.25	376,000	375,119
Federation des caisses Desjardin
5/26/20 to 8/28/20	1.38 to 1.61	255,000	254,221
Landesbank Baden-Wurttemberg
5/1/20	0.05	776,000	776,000
Mitsubishi UFJ Trust & Banking Corp.
5/11/20 to 5/18/20	1.69 to 1.71	193,650	193,528
Natexis Banques Populaires New York Branch
6/24/20	1.61	152,000	151,635
National Bank of Canada
5/8/20	1.90	172,000	171,937
Royal Bank of Canada
8/25/20 to 9/14/20	0.91 to 1.76 (b)	1,547,000	1,543,202
Sumitomo Mitsui Trust Bank Ltd.
5/5/20	1.85	124,000	123,975
Sumitomo Trust & Banking Co. Ltd.
7/20/20 to 7/22/20	0.68 to 0.75	120,500	120,303
Svenska Handelsbanken AB
9/4/20	0.92	345,000	343,895
The Toronto-Dominion Bank
5/5/20 to 11/10/20	0.90 to 2.08 (b)	2,258,200	2,258,086
Toyota Motor Credit Corp.
7/2/20	1.50 (b)(c)	63,000	63,000
TOTAL FINANCIAL COMPANY COMMERCIAL PAPER
(Cost $9,233,534)			9,233,534

Asset Backed Commercial Paper - 0.3%
Manhattan Asset Funding Co. LLC (Liquidity Facility Sumitomo Mitsui Banking Corp.)

5/7/20	1.60	18,000	17,995
6/8/20	0.53	72,000	71,960
Sheffield Receivables Corp. (Liquidity Facility Barclays Bank PLC)

5/11/20	1.69	63,000	62,971
5/11/20	1.69	31,000	30,986
TOTAL ASSET BACKED COMMERCIAL PAPER
(Cost $183,912)			183,912

U.S. Treasury Debt - 25.4%
U.S. Treasury Obligations - 25.4%
U.S. Treasury Bills
5/5/20 to 9/29/20	0.08 to 0.29	13,789,875	13,785,682
U.S. Treasury Notes
10/31/21	0.43 (b)(c)	84,000	84,025
TOTAL U.S. TREASURY DEBT
(Cost $13,869,707)			13,869,707

Other Instrument - 0.3%
Master Notes - 0.3%
Toyota Motor Credit Corp.
5/7/20
(Cost $162,000)	0.39 (b)(c)(e)	162,000	162,000

Variable Rate Demand Note - 0.4%
Arizona - 0.0%
Arizona Health Facilities Auth. Rev. (Catholic Healthcare West Proj.) Series 2008 B, 0.25% 5/7/20, LOC Barclays Bank PLC, VRDN
5/7/20	0.25 (b)	11,300	11,300
California - 0.1%
California Health Facilities Fing. Auth. Rev. (Catholic Healthcare West Proj.) Series 2005 H, 0.2% 5/7/20, LOC Sumitomo Mitsui Banking Corp., VRDN
5/7/20	0.20 (b)	27,125	27,125
Florida - 0.1%
Florida Timber Fin. III LLC Taxable, LOC Wells Fargo Bank NA, VRDN
5/7/20	0.60 (b)	40,000	40,000
Illinois - 0.1%
Chicago O'Hare Int'l. Arpt. Rev. Series 2005 D, 0.23% 5/7/20, LOC Barclays Bank PLC, VRDN
5/7/20	0.23 (b)	34,200	34,200
Illinois Dev. Fin. Auth. Rev. (Lyric Opera of Chicago Proj.) 0.24% 5/7/20, LOC BMO Harris Bank NA, LOC Northern Trust Co., VRDN
5/7/20	0.24 (b)	17,600	17,600
			51,800
Louisiana - 0.0%
Louisiana Offshore Term. Auth. Deepwater Port Rev. (LOOP LLC Proj.) Series 2013 B, 0.26% 5/7/20, LOC JPMorgan Chase Bank, VRDN
5/7/20	0.26 (b)	11,425	11,425
Nevada - 0.0%
Clark County Arpt. Rev. Series 2008 B2, 0.23% 5/7/20, LOC State Street Bank & Trust Co., Boston, VRDN
5/7/20	0.23 (b)(f)	11,900	11,900
Clark County Arpt. Rev. Series 2008 D 2A, 0.2% 5/7/20, LOC Wells Fargo Bank NA, VRDN
5/7/20	0.20 (b)	9,100	9,100
			21,000
New York - 0.1%
New York City Gen. Oblig. Series D5, 0.25% 5/7/20, LOC PNC Bank NA, VRDN
5/7/20	0.25 (b)	9,950	9,950
New York City Hsg. Dev. Corp. Multi-family Mtg. Rev. (Related-Upper East Proj.) Series A, 0.2% 5/7/20, LOC Landesbank Baden-Wurttemberg, VRDN
5/7/20	0.20 (b)(f)	19,300	19,300
			29,250
Pennsylvania - 0.0%
Philadelphia Gas Works Rev. (1998 Gen. Ordinance Proj.) Eighth Series C, 0.2% 5/7/20, LOC Barclays Bank PLC, VRDN
5/7/20	0.20 (b)	9,485	9,485
Wisconsin - 0.0%
Green Bay Redev. Auth. (Green Bay Packaging, Inc. Proj.) 0.3% 5/7/20, LOC Wells Fargo Bank NA, VRDN
5/7/20	0.30 (b)(d)(f)	15,600	15,600
TOTAL VARIABLE RATE DEMAND NOTE
(Cost $216,985)			216,985

Non-Negotiable Time Deposit - 5.7%
Time Deposits - 5.7%
Barclays Bank PLC
5/1/20	0.18	1,551,000	1,551,000
Credit Agricole CIB
5/1/20 to 5/6/20	0.05 to 0.15	483,219	483,219
Landesbank Hessen-Thuringen London Branch
5/1/20 to 5/7/20	0.15	400,000	400,000
Mizuho Bank Ltd.
5/1/20	0.06	698,000	698,000
TOTAL NON-NEGOTIABLE TIME DEPOSIT
(Cost $3,132,219)			3,132,219

Interfund Loans - 0.1%
With:
Fidelity Total Market Index Fund, at 0.28%
due 5/1/20		34,832	34,832
Fidelity SAI Small-Mid Cap 500 Index Fund, at 0.28%
due 5/1/20		1,439	1,439
TOTAL INTERFUND LOANS
(Cost $36,271)			36,271

U.S. Government Agency Repurchase Agreement - 7.3%
	Maturity Amount (000s)	Value (000s)
In a joint trading account at 0.05% dated 4/30/20 due 5/1/20 (Collateralized by (U.S. Government Obligations) #	$3,262,749	$3,262,744
With:
BMO Harris Bank NA at 0.06%, dated 4/30/20 due 5/1/20 (Collateralized by Mortgage Loan Obligations valued at $15,450,026, 1.17% - 3.00%, 1/20/49 - 2/25/50)	15,000	15,000
Deutsche Bank AG, New York at 0.06%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $60,770,101, 3.05% - 3.35%, 6/15/24 - 4/15/45)	59,000	59,000
Goldman Sachs & Co. at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $306,000,425, 2.50% - 6.00%, 6/1/26 - 5/15/60)	300,000	300,000
Morgan Stanley & Co., LLC at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $172,381,192, 0.00% - 6.00%, 2/1/24 - 5/1/50)	169,000	169,000
RBC Financial Group at 0.06%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $170,250,618, 1.17% - 4.50%, 7/1/33 - 3/1/50)	166,000	166,000
TOTAL U.S. GOVERNMENT AGENCY REPURCHASE AGREEMENT
(Cost $3,971,744)		3,971,744

U.S. Treasury Repurchase Agreement - 2.7%
With:
BNP Paribas, SA at 1.61%, dated 2/18/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $200,553,493, 0.00% - 8.13%, 3/25/21 - 2/15/50)	195,785	195,000
Deutsche Bank AG, New York at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $285,600,506, 1.75% - 3.13%, 11/15/20 - 11/15/28)	280,000	280,000
Deutsche Bank Securities, Inc. at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $9,180,101, 2.63%, 7/31/20)	9,000	9,000
Fixed Income Clearing Corp. - BNYM at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $215,220,072, 2.75%, 2/15/28)	211,000	211,000
SMBC Nikko Securities America, Inc. at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $785,120,047, 2.00% - 2.38%, 11/15/26 - 5/15/27)	770,001	770,000
TOTAL U.S. TREASURY REPURCHASE AGREEMENT
(Cost $1,465,000)		1,465,000

Other Repurchase Agreement - 10.2%
Other Repurchase Agreement - 10.2%
With:
BMO Capital Markets Corp. at:
0.3%, dated 4/30/20 due 5/1/20 (Collateralized by Corporate Obligations valued at $140,702,175, 1.20% - 11.50%, 4/1/23 - 8/26/49)	134,001	134,000
0.37%, dated 4/30/20 due 5/1/20 (Collateralized by Equity Securities valued at $356,403,735)	330,003	330,000
0.39%, dated 4/30/20 due 5/1/20 (Collateralized by Corporate Obligations valued at $368,287,039, 2.65% - 10.00%, 6/1/20 - 8/8/46)	342,004	342,000
BNP Paribas at 0.24%, dated 4/30/20 due 5/1/20 (Collateralized by Corporate Obligations valued at $281,401,876, 0.00% - 9.50%, 10/19/20 - 6/1/77)	268,002	268,000
BNP Paribas Prime Brokerage, Inc. at 0.34%, dated 4/30/20 due 5/1/20 (Collateralized by Equity Securities valued at $325,082,969)	301,003	301,000
BofA Securities, Inc. at 0.54%, dated 4/30/20 due 5/1/20 (Collateralized by Mortgage Loan Obligations valued at $116,151,743, 0.54%, 10/25/59)	101,002	101,000
Citigroup Global Markets, Inc. at:
0.3%, dated 4/30/20 due 5/1/20 (Collateralized by Equity Securities valued at $302,402,542)	280,002	280,000
1.17%, dated 4/22/20 due 5/21/20 (Collateralized by U.S. Government Obligations valued at $92,727,598, 0.60% - 6.00%, 12/30/22 - 12/20/43)	90,085	90,000
1.23%, dated 11/12/19 due 5/11/20 (Collateralized by Corporate Obligations valued at $114,548,388, 0.00% - 6.49%, 11/15/21 - 3/25/58)(c)(g)(h)	106,655	106,000
1.43%, dated 3/4/20 due 6/4/20 (Collateralized by Mortgage Loan Obligations valued at $75,760,789, 0.00% - 5.10%, 11/25/27 - 12/10/49)(c)(g)(h)	72,515	72,000
2.07%, dated 2/24/20 due 5/27/20 (Collateralized by U.S. Treasury Obligations valued at $108,536,617, 1.63% - 1.75%, 12/15/22 - 12/31/26)	106,567	106,000
Credit AG CIB Paris at:
0.34%, dated 4/30/20 due 5/1/20 (Collateralized by Corporate Obligations valued at $192,690,071, 2.00% - 4.42%, 11/2/20 - 9/10/28)	185,002	185,000
0.65%, dated 4/22/20 due 5/7/20 (Collateralized by Corporate Obligations valued at $187,980,542, 2.00% - 4.25%, 11/2/20 - 1/15/27)	179,097	179,000
Credit Suisse Securities (U.S.A.) LLC at 1.66%, dated 3/2/20 due 7/6/20 (Collateralized by Corporate Obligations valued at $94,761,450, 0.19% - 7.00%, 11/15/24 - 1/17/73)	90,623	90,000
Deutsche Bank AG at 0.54%, dated 4/30/20 due 5/1/20 (Collateralized by Municipal Bond Obligations valued at $222,170,533, 0.00% - 5.25%, 1/1/22 - 11/1/59)	211,003	211,000
HSBC Securities, Inc. at 0.39%, dated 4/30/20 due 5/1/20 (Collateralized by Corporate Obligations valued at $238,092,982, 2.10% - 6.70%, 5/18/20 - 3/1/57)	227,002	227,000
ING Financial Markets LLC at:
0.29%, dated 4/30/20 due 5/1/20 (Collateralized by Corporate Obligations valued at $21,000,169, 2.00% - 5.00%, 6/9/21 - 4/15/50)	20,000	20,000
0.3%, dated 4/30/20 due 5/1/20 (Collateralized by Equity Securities valued at $44,280,403)	41,000	41,000
1.32%, dated 3/5/20 due 5/4/20 (Collateralized by Equity Securities valued at $115,801,555)	107,235	107,000
J.P. Morgan Securities, LLC at 0.44%, dated 4/6/20 due 5/7/20 (Collateralized by Equity Securities valued at $462,383,295)(c)(g)(h)	428,157	428,000
Mitsubishi UFJ Securities (U.S.A.), Inc. at:
0.29%, dated 4/30/20 due 5/1/20 (Collateralized by Equity Securities valued at $166,321,343)	154,001	154,000
0.59%, dated 4/30/20 due 5/1/20 (Collateralized by Corporate Obligations valued at $11,866,466, 0.75% - 7.50%, 9/15/20 - 3/15/49)	11,000	11,000
Mizuho Securities U.S.A., Inc. at:
0.51%, dated 4/30/20 due 5/1/20 (Collateralized by Equity Securities valued at $349,924,962)	324,005	324,000
1.04%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $128,523,713, 2.50%, 4/1/50)	126,004	126,000
Morgan Stanley & Co., Inc. at 2.08%, dated 2/5/20 due 5/5/20 (Collateralized by Equity Securities valued at $18,451,926)	17,088	17,000
RBS Securities, Inc. at 0.35%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $110,162,201, 0.00% - 8.63%, 7/15/20 - 3/7/44)	108,001	108,000
Societe Generale at:
0.35%, dated 4/30/20 due 5/1/20 (Collateralized by Corporate Obligations valued at $238,333,913, 0.00% - 6.45%, 8/10/20 - 4/1/60)	227,002	227,000
0.4%, dated 4/30/20 due 5/1/20 (Collateralized by Corporate Obligations valued at $396,441,523, 0.64% - 12.00%, 7/15/20 - 12/31/99)	370,004	370,000
0.45%, dated 4/30/20 due 5/1/20 (Collateralized by Corporate Obligations valued at $174,962,187, 0.62% - 10.50%, 4/4/21 - 7/10/48)	162,002	162,000
0.5%, dated 4/28/20 due 5/5/20 (Collateralized by Corporate Obligations valued at $131,057,190, 0.13% - 12.00%, 8/31/20 - 6/10/75)	122,012	122,000
0.55%, dated 4/28/20 due 5/5/20 (Collateralized by Corporate Obligations valued at $44,268,733, 0.63% - 10.50%, 11/16/20 - 12/16/72)	41,004	41,000
Wells Fargo Securities, LLC at:
0.24%, dated 4/30/20 due 5/1/20 (Collateralized by Commercial Paper valued at $84,460,564, 0.00%, 1/5/21 - 1/15/21)	82,001	82,000
0.54%, dated 4/30/20 due 5/1/20 (Collateralized by Corporate Obligations valued at $44,280,664, 1.38% - 4.75%, 11/1/22 - 6/15/26)	41,001	41,000
0.65%, dated:
4/27/20 due 5/4/20 (Collateralized by Corporate Obligations valued at $44,283,198, 4.50% - 5.25%, 2/1/24 - 6/1/24)	41,005	41,000
4/30/20 due 5/7/20 (Collateralized by Corporate Obligations valued at $130,682,360, 0.75% - 5.25%, 9/15/20 - 8/15/28)	121,015	121,000
TOTAL OTHER REPURCHASE AGREEMENT
(Cost $5,565,000)		5,565,000
TOTAL INVESTMENT IN SECURITIES - 101.8%
(Cost $55,631,993)		55,631,993
NET OTHER ASSETS (LIABILITIES) - (1.8)%		(968,979)
NET ASSETS - 100%		$54,663,014

Security Type Abbreviations

VRDN – VARIABLE RATE DEMAND NOTE (A debt instrument that is payable upon demand, either daily, weekly or monthly)

Legend

(a) Yield represents either the annualized yield at the date of purchase, or the stated coupon rate, or, for floating and adjustable rate securities, the rate at period end.

(b) Coupon rates for floating and adjustable rate securities reflect the rates in effect at period end.

(c) Coupon is indexed to a floating interest rate which may be multiplied by a specified factor and/or subject to caps or floors.

(d) Security exempt from registration under Rule 144A of the Securities Act of 1933. These securities may be resold in transactions exempt from registration, normally to qualified institutional buyers. At the end of the period, the value of these securities amounted to $82,600,000 or 0.2% of net assets.

(e) Restricted securities (including private placements) - Investment in securities not registered under the Securities Act of 1933 (excluding 144A issues). At the end of the period, the value of restricted securities (excluding 144A issues) amounted to $162,000,000 or 0.3% of net assets.

(f) Private activity obligations whose interest is subject to the federal alternative minimum tax for individuals.

(g) Coupon rates for floating and adjustable rate securities reflect the rates in effect at period end.

(h) The maturity amount is based on the rate at period end.

Additional information on each restricted holding is as follows:

Security	Acquisition Date	Cost
Toyota Motor Credit Corp. 0.39%, 5/7/20	3/2/20	$162,000,000

Investment Valuation

Other Information

# Additional information on each counterparty to the repurchase agreement is as follows:

Repurchase Agreement / Counterparty	Value (000s)
$3,262,744,000 due 5/01/20 at 0.05%
BNP Paribas, S.A.	$28,232
BNY Mellon Capital Markets LLC	136,036
Bank Of America, N.A.	269,671
Citibank NA	74,909
Citigroup Global Markets, Inc.	164,153
Credit Agricole CIB New York Branch	157,308
ING Financial Markets LLC	28,409
Jp Morgan Secs Llc	661,921
Mitsubishi Ufj Secs Hldgs Ltd	190,581
Mitsubishi Ufj Securities (USA	18,727
Mizuho Securities USA, Inc.	134,835
Societe Generale (PARIS)	172,364
Sumitomo Mitsu Bk Corp Ny (DI)	254,442
Sumitomo Mitsui Bk Corp (REPO)	870,030
Wells Fargo Securities LLC	101,126
	$3,262,744

See accompanying notes which are an integral part of the financial statements.

Financial Statements

Statement of Assets and Liabilities

Amounts in thousands (except per-share amounts)		April 30, 2020
Assets
Investment in securities, at value (including repurchase agreements of $11,001,744) — See accompanying schedule: Unaffiliated issuers (cost $55,595,722)	$55,595,722
Affiliated issuers (cost $36,271)	36,271
Total Investment in Securities (cost $55,631,993)		$55,631,993
Receivable for fund shares sold		308,539
Interest receivable		26,367
Prepaid expenses		19
Receivable from investment adviser for expense reductions		2,547
Other receivables		224
Total assets		55,969,689
Liabilities
Payable for investments purchased	$1,089,879
Payable for fund shares redeemed	196,626
Distributions payable	1,622
Accrued management fee	11,214
Other affiliated payables	4,919
Other payables and accrued expenses	2,415
Total liabilities		1,306,675
Net Assets		$54,663,014
Net Assets consist of:
Paid in capital		$54,662,832
Total accumulated earnings (loss)		182
Net Assets		$54,663,014
Net Asset Value and Maximum Offering Price
Fidelity Money Market Fund:
Net Asset Value, offering price and redemption price per share ($6,092,666 ÷ 6,092,598 shares)		$1.00
Premium Class:
Net Asset Value, offering price and redemption price per share ($48,570,348 ÷ 48,567,412 shares)		$1.00

See accompanying notes which are an integral part of the financial statements.

Statement of Operations

Amounts in thousands		Year ended April 30, 2020
Investment Income
Interest (including $311 from affiliated interfund lending)		991,913
Expenses
Management fee	$125,287
Transfer agent fees	53,477
Accounting fees and expenses	1,911
Custodian fees and expenses	572
Independent trustees' fees and expenses	183
Registration fees	2,728
Audit	44
Legal	57
Interest	468
Miscellaneous	134
Total expenses before reductions	184,861
Expense reductions	(27,131)
Total expenses after reductions		157,730
Net investment income (loss)		834,183
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment securities:
Unaffiliated issuers	79
Total net realized gain (loss)		79
Net increase in net assets resulting from operations		$834,262

See accompanying notes which are an integral part of the financial statements.

Statement of Changes in Net Assets

Amounts in thousands	Year ended April 30, 2020	Year ended April 30, 2019
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$834,183	$646,637
Net realized gain (loss)	79	115
Net increase in net assets resulting from operations	834,262	646,752
Distributions to shareholders	(834,183)	(646,632)
Share transactions - net increase (decrease)	12,485,517	23,471,138
Total increase (decrease) in net assets	12,485,596	23,471,258
Net Assets
Beginning of period	42,177,418	18,706,160
End of period	$54,663,014	$42,177,418

See accompanying notes which are an integral part of the financial statements.

Financial Highlights

Fidelity Money Market Fund

Years ended April 30,	2020	2019	2018	2017	2016
Selected Per–Share Data
Net asset value, beginning of period	$1.00	$1.00	$1.00	$1.00	$1.00
Income from Investment Operations
Net investment income (loss)	.016	.020	.011	.005	.001
Net realized and unrealized gain (loss)^A	–	–	–	–	–
Total from investment operations	.016	.020	.011	.005	.001
Distributions from net investment income	(.016)	(.020)	(.011)	(.005)	(.001)
Total distributions	(.016)	(.020)	(.011)	(.005)	(.001)
Net asset value, end of period	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return^B	1.61%	2.03%	1.11%	.52%	.09%
Ratios to Average Net Assets^C
Expenses before reductions	.42%	.42%	.42%	.42%	.42%
Expenses net of fee waivers, if any	.42%	.42%	.42%	.42%	.36%
Expenses net of all reductions	.42%	.42%	.42%	.42%	.36%
Net investment income (loss)	1.56%	2.06%	1.15%	.55%	.15%
Supplemental Data
Net assets, end of period (in millions)	$6,093	$5,196	$3,209	$2,301	$2,126

^A Amount represents less than $.0005 per share.

^B Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^C Expense ratios reflect operating expenses of the class. Expenses before reductions do not reflect amounts reimbursed or waived or reductions from expense offset arrangements and do not represent the amount paid by the class during periods when reimbursements, waivers or reductions occur. Expenses net of fee waivers reflect expenses after reimbursement and waivers but prior to reductions from expense offset arrangements. Expenses net of all reductions represent the net expenses paid by the class.

See accompanying notes which are an integral part of the financial statements.

Fidelity Money Market Fund Premium Class

Years ended April 30,	2020	2019	2018	2017	2016
Selected Per–Share Data
Net asset value, beginning of period	$1.00	$1.00	$1.00	$1.00	$1.00
Income from Investment Operations
Net investment income (loss)	.017	.021	.012	.006	.002
Net realized and unrealized gain (loss)^A	–	–	–	–	–
Total from investment operations	.017	.021	.012	.006	.002
Distributions from net investment income	(.017)	(.021)	(.012)	(.006)	(.002)
Total distributions	(.017)	(.021)	(.012)	(.006)	(.002)
Net asset value, end of period	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return^B,^C	1.73%	2.16%	1.23%	.64%	.15%
Ratios to Average Net Assets^D
Expenses before reductions	.36%	.37%	.37%	.37%	.37%
Expenses net of fee waivers, if any	.30%	.30%	.30%	.30%	.30%
Expenses net of all reductions	.30%	.30%	.30%	.30%	.30%
Net investment income (loss)	1.68%	2.18%	1.27%	.67%	.20%
Supplemental Data
Net assets, end of period (in millions)	$48,570	$36,981	$15,497	$7,317	$3,706

^A Amount represents less than $.0005 per share.

^B Total returns for periods of less than one year are not annualized.

^C Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^D Expense ratios reflect operating expenses of the class. Expenses before reductions do not reflect amounts reimbursed or waived or reductions from expense offset arrangements and do not represent the amount paid by the class during periods when reimbursements, waivers or reductions occur. Expenses net of fee waivers reflect expenses after reimbursement and waivers but prior to reductions from expense offset arrangements. Expenses net of all reductions represent the net expenses paid by the class.

See accompanying notes which are an integral part of the financial statements.

Notes to Financial Statements

For the period ended April 30, 2020
(Amounts in thousands except percentages)

1. Organization.

Fidelity Money Market Fund (the Fund) is a fund of Fidelity Hereford Street Trust (the Trust) and is authorized to issue an unlimited number of shares. The Trust is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company organized as a Delaware statutory trust. The Fund offers Fidelity Money Market Fund and Premium Class shares, each of which has equal rights as to assets and voting privileges. Each class has exclusive voting rights with respect to matters that affect that class. Shares of the Fund are only available for purchase by retail shareholders.

Effective January 1, 2020:

Fidelity Investments Institutional Operations Company, Inc. converted from a Massachusetts corporation to a Massachusetts LLC, and changed its name to "Fidelity Investments Institutional Operations Company LLC".

2. Significant Accounting Policies.

Investment Valuation. The Fund categorizes the inputs to valuation techniques used to value its investments into a disclosure hierarchy consisting of three levels as shown below:

Level 1 – quoted prices in active markets for identical investments
Level 2 – other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, etc.)
Level 3 – unobservable inputs (including the Fund's own assumptions based on the best information available)

Class Allocations and Expenses. Investment income, realized and unrealized capital gains and losses, common expenses of the Fund, and certain fund-level expense reductions, if any, are allocated daily on a pro-rata basis to each class based on the relative net assets of each class to the total net assets of the Fund. Each class differs with respect to transfer agent fees incurred. Certain expense reductions may also differ by class. For the reporting period, the allocated portion of income and expenses to each class as a percent of its average net assets may vary due to the timing of recording these transactions in relation to fluctuating net assets of the classes. Expenses directly attributable to a fund are charged to that fund. Expenses attributable to more than one fund are allocated among the respective funds on the basis of relative net assets or other appropriate methods. Expense estimates are accrued in the period to which they relate and adjustments are made when actual amounts are known.

Deferred Trustee Compensation. Under a Deferred Compensation Plan (the Plan) for the Fund, certain independent Trustees have elected to defer receipt of a portion of their annual compensation. Deferred amounts are invested in a cross-section of Fidelity funds, are marked-to-market and remain in the Fund until distributed in accordance with the Plan. The investment of deferred amounts and the offsetting payable to the Trustees of $224 are included in the accompanying Statement of Assets and Liabilities in other receivables and other payables and accrued expenses, respectively.

Distributions are declared and recorded daily and paid monthly from net investment income. Distributions from realized gains, if any, are declared and recorded on the ex-dividend date. Income and capital gain distributions are declared separately for each class. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from GAAP. In addition, the Fund claimed a portion of the payment made to redeeming shareholders as a distribution for income tax purposes.

Book-tax differences are primarily due to deferred trustees compensation.

As of period end, the cost and unrealized appreciation (depreciation) in securities for federal income tax purposes were as follows:

Gross unrealized appreciation	$–
Gross unrealized depreciation	–
Net unrealized appreciation (depreciation)	$–
Tax Cost	$55,631,993

The tax-based components of distributable earnings as of period end were as follows:

Undistributed ordinary income

$406

The tax character of distributions paid was as follows:

	April 30, 2020	April 30, 2019
Ordinary Income	$834,183	$ 646,632

Repurchase Agreements. Pursuant to an Exemptive Order issued by the Securities and Exchange Commission (the SEC), the Fund along with other registered investment companies having management contracts with Fidelity Management & Research Company LLC (FMR), or other affiliated entities of FMR, are permitted to transfer uninvested cash balances into joint trading accounts which are then invested in repurchase agreements. The Fund may also invest directly with institutions in repurchase agreements. Repurchase agreements may be collateralized by government or non-government securities. Upon settlement date, collateral is held in segregated accounts with custodian banks and may be obtained in the event of a default of the counterparty. The Fund monitors, on a daily basis, the value of the collateral to ensure it is at least equal to the principal amount of the repurchase agreement (including accrued interest). In the event of a default by the counterparty, realization of the collateral proceeds could be delayed, during which time the value of the collateral may decline.

Reverse Repurchase Agreements. To enhance its yield, the Fund may enter into reverse repurchase transactions under master repurchase agreements whereby the Fund sells securities to a counterparty in return for cash and agrees to repurchase those securities at a future date and agreed upon price. During the period that reverse repurchase transactions are outstanding, the Fund identifies the securities as pledged in its records with an initial value at least equal to its principal obligation under the agreement. The cash proceeds received by the Fund may be invested in other securities. To the extent cash proceeds received from the counterparty exceed the value of the securities sold, the counterparty may request additional collateral from the Fund. If the counterparty defaults on its obligation, because of insolvency or other reasons, the Fund could experience delays and costs in recovering the securities sold. Information regarding securities sold under a reverse repurchase agreement, if any, is included at the end of the Fund's Schedule of Investments and the cash proceeds are recorded as a liability in the accompanying Statement of Assets and Liabilities. The Fund continues to receive interest and dividend payments on the securities sold during the term of the reverse repurchase agreement. During the period, the average principal balance of reverse repurchase transactions was $52,549 and the weighted average interest rate was 2.11% with payments included in the Statement of Operations as a component of interest expense. At period end, there were no reverse repurchase agreements outstanding.

Restricted Securities (including Private Placements). The Fund may invest in securities that are subject to legal or contractual restrictions on resale. These securities generally may be resold in transactions exempt from registration or to the public if the securities are registered. Disposal of these securities may involve time-consuming negotiations and expense, and prompt sale at an acceptable price may be difficult. Information regarding restricted securities is included at the end of the Fund's Schedule of Investments.

3. Fees and Other Transactions with Affiliates.

Management Fee. Fidelity Management & Research Company LLC (the investment adviser) and its affiliates provide the Fund with investment management related services for which the Fund pays a monthly management fee that is based on an annual rate of .25% of the Fund's average net assets. Under the expense contract, total expenses of Fidelity Money Market Fund are limited to an annual rate of .42% of the class' average net assets, with certain exceptions.

Transfer Agent Fees. Fidelity Investments Institutional Operations Company LLC (FIIOC), an affiliate of the investment adviser, is the transfer, dividend disbursing and shareholder servicing agent for each class of the Fund. FIIOC receives asset-based fees with respect to each account. FIIOC pays for typesetting, printing and mailing of shareholder reports, except proxy statements. Premium Class pays a transfer agent fee equal to an annual rate of .10% of class-level average net assets.

Under the expense contract, Fidelity Money Market Fund will pay a portion of the transfer agent fee at an annual rate of up to .17% of class-level average net assets.

For the period, transfer agent fees for each class were as follows:

	Amount	% of Class-Level Average Net Assets
Fidelity Money Market Fund	$9,067	.16
Premium Class	44,410	.10
	$53,477

Accounting Fees. Fidelity Service Company, Inc. (FSC), an affiliate of the investment adviser, maintains the Fund's accounting records. The accounting fee is based on the level of average net assets for each month. For the period, the fees were equivalent to less than .005%.

Interfund Lending Program. Pursuant to an Exemptive Order issued by the SEC, the fund, along with other registered investment companies having management contracts with FMR, or other affiliated entities of FMR, may participate in an interfund lending program. This program provides an alternative credit facility allowing the fund to borrow from, or lend money to, other participating affiliated funds. Any open loans at period end are presented under the caption "Interfund Loans" in the Schedule of Investments with accrued interest included in Other affiliated receivables on the Statement of Assets and Liabilities. Activity in this program during the period for which loans were outstanding was as follows:

		Average Loan Balance	Weighted Average Interest Rate
Fidelity Money Market Fund	Lender	31,568	1.83%

Other. During the period, the investment adviser reimbursed the Fund for certain losses in the amount of $2.

4. Expense Reductions.

The investment adviser contractually agreed to reimburse Premium Class to the extent annual operating expenses exceeded .30% of the average net assets. This reimbursement will remain in place through August 31, 2020. Some expenses, for example the compensation of the independent Trustees, and certain other expenses such as interest expense, are excluded from this reimbursement. During the period, this reimbursement reduced Premium Class' expenses by $27,121.

Through arrangements with the Fund's custodian and each class' transfer agent, credits realized as a result of certain uninvested cash balances were used to reduce the Fund's expenses. During the period, custodian credits reduced the Fund's expenses by $8. During the period, Transfer agent credits reduced each class' expenses as noted in the table below.

	Expense Reduction
Fidelity Money Market Fund	$1

In addition, during the period, the investment adviser or an affiliate reimbursed the Fund $1 for an operational error which is included in the accompanying Statement of Operations.

5. Distributions to Shareholders.

Distributions to shareholders of each class were as follows:

	Year ended April 30, 2020	Year ended April 30, 2019
Distributions to shareholders
Fidelity Money Market Fund	$89,701	$85,070
Premium Class	744,482	561,562
Total	$834,183	$646,632

6. Share Transactions.

Share transactions for each class of shares at a $1.00 per share were as follows and may contain automatic conversions between classes or exchanges between affiliated funds:

	Shares	Shares	Dollars	Dollars
	Year ended April 30, 2020	Year ended April 30, 2019	Year ended April 30, 2020	Year ended April 30, 2019
Fidelity Money Market Fund
Shares sold	7,092,098	6,378,152	$7,092,098	$6,378,152
Reinvestment of distributions	81,987	77,567	81,987	77,567
Shares redeemed	(6,277,347)	(4,468,699)	(6,277,347)	(4,468,699)
Net increase (decrease)	896,738	1,987,020	$896,738	$1,987,020
Premium Class
Shares sold	54,365,984	45,986,467	$54,365,984	$45,986,467
Reinvestment of distributions	684,700	514,820	684,700	514,820
Shares redeemed	(43,461,905)	(25,017,169)	(43,461,905)	(25,017,169)
Net increase (decrease)	11,588,779	21,484,118	$11,588,779	$21,484,118

7. Other.

8. Coronavirus (COVID-19) Pandemic.

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of Fidelity Hereford Street Trust and Shareholders of Fidelity Money Market Fund

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Fidelity Money Market Fund (one of the funds constituting Fidelity Hereford Street Trust, referred to hereafter as the “Fund”) as of April 30, 2020, the related statement of operations for the year ended April 30, 2020, the statement of changes in net assets for each of the two years in the period ended April 30, 2020, including the related notes, and the financial highlights for each of the five years in the period ended April 30, 2020 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Fund as of April 30, 2020, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended April 30, 2020 and the financial highlights for each of the five years in the period ended April 30, 2020 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of April 30, 2020 by correspondence with the custodians and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

PricewaterhouseCoopers LLP

Boston, Massachusetts

June 10, 2020

We have served as the auditor of one or more investment companies in the Fidelity group of funds since 1932.

Trustees and Officers

The fund’s Statement of Additional Information (SAI) includes more information about the Trustees. To request a free copy, call Fidelity at 1-800-544-8544.

Interested Trustees*:

Correspondence intended for a Trustee who is an interested person may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Abigail P. Johnson (1961)

Year of Election or Appointment: 2009

Trustee

Chairman of the Board of Trustees

Jennifer Toolin McAuliffe (1959)

Year of Election or Appointment: 2016

Trustee

* Determined to be an “Interested Trustee” by virtue of, among other things, his or her affiliation with the trust or various entities under common control with FMR.

Independent Trustees:

Correspondence intended for an Independent Trustee may be sent to Fidelity Investments, P.O. Box 55235, Boston, Massachusetts 02205-5235.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Elizabeth S. Acton (1951)

Year of Election or Appointment: 2013

Trustee

Ann E. Dunwoody (1953)

Year of Election or Appointment: 2018

Trustee

John Engler (1948)

Year of Election or Appointment: 2014

Trustee

Robert F. Gartland (1951)

Year of Election or Appointment: 2010

Trustee

Arthur E. Johnson (1947)

Year of Election or Appointment: 2008

Trustee

Chairman of the Independent Trustees

Michael E. Kenneally (1954)

Year of Election or Appointment: 2009

Trustee

Vice Chairman of the Independent Trustees

Marie L. Knowles (1946)

Year of Election or Appointment: 2001

Trustee

Mark A. Murray (1954)

Year of Election or Appointment: 2016

Trustee

Advisory Board Members and Officers:

Correspondence intended for an officer may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210. Officers appear below in alphabetical order.

Name, Year of Birth; Principal Occupation

Elizabeth Paige Baumann (1968)

Year of Election or Appointment: 2017

Anti-Money Laundering (AML) Officer

Craig S. Brown (1977)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Brown also serves as Assistant Treasurer of other funds. Mr. Brown is an employee of Fidelity Investments (2013-present).

John J. Burke III (1964)

Year of Election or Appointment: 2018

Chief Financial Officer

David J. Carter (1973)

Year of Election or Appointment: 2020

Assistant Secretary

Mr. Carter also serves as Assistant Secretary of other funds. Mr. Carter serves as Vice President, Associate General Counsel (2010-present) and is an employee of Fidelity Investments (2005-present).

Jonathan Davis (1968)

Year of Election or Appointment: 2010

Assistant Treasurer

Laura M. Del Prato (1964)

Year of Election or Appointment: 2018

President and Treasurer

Colm A. Hogan (1973)

Year of Election or Appointment: 2016

Assistant Treasurer

Cynthia Lo Bessette (1969)

Year of Election or Appointment: 2019

Secretary and Chief Legal Officer (CLO)

Chris Maher (1972)

Year of Election or Appointment: 2013

Assistant Treasurer

Nancy D. Prior (1967)

Year of Election or Appointment: 2014

Vice President

Kenneth B. Robins (1969)

Year of Election or Appointment: 2020

Chief Compliance Officer

Stacie M. Smith (1974)

Year of Election or Appointment: 2013

Assistant Treasurer

Marc L. Spector (1972)

Year of Election or Appointment: 2016

Deputy Treasurer

Jim Wegmann (1979)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Wegmann also serves as Assistant Treasurer of other funds. Mr. Wegmann is an employee of Fidelity Investments (2011-present).

Shareholder Expense Example

The Example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period (November 1, 2019 to April 30, 2020).

Actual Expenses

The first line of the accompanying table for each class of the Fund provides information about actual account values and actual expenses. You may use the information in this line, together with the amount you invested, to estimate the expenses that you paid over the period. Simply divide your account value by $1,000.00 (for example, an $8,600 account value divided by $1,000.00 = 8.6), then multiply the result by the number in the first line for a class of the Fund under the heading entitled "Expenses Paid During Period" to estimate the expenses you paid on your account during this period.

Hypothetical Example for Comparison Purposes

The second line of the accompanying table for each class of the Fund provides information about hypothetical account values and hypothetical expenses based on a Class' actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Class' actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the Fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds.

	Annualized Expense Ratio-^A	Beginning Account Value November 1, 2019	Ending Account Value April 30, 2020	Expenses Paid During Period-^B November 1, 2019 to April 30, 2020
Fidelity Money Market Fund	.42%
Actual		$1,000.00	$1,006.00	$2.09
Hypothetical-^C		$1,000.00	$1,022.77	$2.11
Premium Class	.30%
Actual		$1,000.00	$1,006.60	$1.50
Hypothetical-^C		$1,000.00	$1,023.37	$1.51

^A Annualized expense ratio reflects expenses net of applicable fee waivers.

^B Expenses are equal to each Class' annualized expense ratio, multiplied by the average account value over the period, multiplied by 182/366 (to reflect the one-half year period).

^C 5% return per year before expenses

Distributions (Unaudited)

A total of 1.11% of the dividends distributed during the fiscal year was derived from interest on U.S. Government securities which is generally exempt from state income tax.

The fund designates $96,363,637 of distributions paid during the period January 1, 2020 to April 30, 2020 as qualifying to be taxed as interest-related dividends for nonresident alien shareholders.

The fund will notify shareholders in January 2021 of amounts for use in preparing 2020 income tax returns.

Fidelity Investments

SPM-ANN-0620
1.703534.122

Fidelity® Government Money Market Fund

Annual Report

April 30, 2020

See the inside front cover for important information about access to your fund’s shareholder reports.

Fidelity Investments

Account Type	Website	Phone Number
Brokerage, Mutual Fund, or Annuity Contracts:	fidelity.com/mailpreferences	1-800-343-3548
Employer Provided Retirement Accounts:	netbenefits.fidelity.com/preferences (choose 'no' under Required Disclosures to continue to print)	1-800-343-0860
Advisor Sold Accounts Serviced Through Your Financial Intermediary:	Contact Your Financial Intermediary	Your Financial Intermediary's phone number
Advisor Sold Accounts Serviced by Fidelity:	institutional.fidelity.com	1-877-208-0098

Contents

Note to Shareholders
Investment Summary/Performance
Schedule of Investments
Financial Statements
Notes to Financial Statements
Report of Independent Registered Public Accounting Firm
Trustees and Officers
Shareholder Expense Example
Distributions

You may also call 1-800-544-8544 if you’re an individual investing directly with Fidelity, call 1-800-835-5092 if you’re a plan sponsor or participant with Fidelity as your recordkeeper or call 1-877-208-0098 on institutional accounts or if you’re an advisor or invest through one to request a free copy of the proxy voting guidelines.

Standard & Poor's, S&P and S&P 500 are registered service marks of The McGraw-Hill Companies, Inc. and have been licensed for use by Fidelity Distributors Corporation.

Other third-party marks appearing herein are the property of their respective owners.

NOT FDIC INSURED •MAY LOSE VALUE •NO BANK GUARANTEE

Neither the Fund nor Fidelity Distributors Corporation is a bank.

Note to Shareholders:

Investment Summary/Performance (Unaudited)

Effective Maturity Diversification

Days	% of fund's investments 04/30/20
1 - 7	56.5
8 - 30	15.2
31 - 60	11.3
61 - 90	5.7
91 - 180	11.0
> 180	0.3

Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940.

Asset Allocation (% of fund's net assets)

As of April 30, 2020
	U.S. Treasury Debt	18.9%
	U.S. Government Agency Debt	43.1%
	Repurchase Agreements	39.8%
	Variable Rate Demand Notes (VRDNs)	0.1%
	Net Other Assets (Liabilities)^*	(1.9)%

* Net Other Assets (Liabilities) are not included in the pie chart

Current 7-Day Yields

	4/30/20
Capital Reserves Class	0.01%
Daily Money Class	0.01%
Advisor M Class	0.01%
Fidelity Government Money Market Fund	0.01%
Premium Class	0.05%
Class K6	0.12%

Yield refers to the income paid by the Fund over a given period. Yield for money market funds is usually for seven-day periods, as it is here, though it is expressed as an annual percentage rate. Past performance is no guarantee of future results. Yield will vary and it's possible to lose money investing in the Fund. A portion of the Fund's expenses was reimbursed and/or waived. Absent such reimbursements and/or waivers the yield for the period ending April 30, 2020, the most recent period shown in the table, would have been (0.63)% for Capital Reserves Class, (0.37)% for Daily Money Class, (0.37)% for Advisor M Class, (0.05)% for Fidelity Government Money Market Fund, (0.02)% for Premium Class and 0.07% for Class K6.

Schedule of Investments April 30, 2020

Showing Percentage of Net Assets

U.S. Treasury Debt - 18.9%
	Yield(a)	Principal Amount	Value
U.S. Treasury Obligations - 18.9%
U.S. Treasury Bills
5/5/20 to 10/6/20	0.08 to 1.83 %	$28,411,300,000	$28,398,742,876
U.S. Treasury Notes
5/31/20 to 1/31/22	0.28 to 1.83 (b)	7,149,701,000	7,159,646,144
TOTAL U.S. TREASURY DEBT
(Cost $35,558,389,020)			35,558,389,020

Variable Rate Demand Note - 0.1%
California - 0.0%
FHLMC California Statewide Cmntys. Dev. Auth. Multi-family Hsg. Rev. (Heritage Park Apts. Proj.) Series 2008 C, 0.19% 5/7/20, LOC Freddie Mac, VRDN
5/7/20	0.19 (b)(c)	9,700,000	9,700,000
FHLMC Los Angeles Cmnty. Redev. Agcy. Multi-family Hsg. Rev. (Grand Promenade Proj.) 0.22% 5/7/20, LOC Freddie Mac, VRDN
5/7/20	0.22 (b)	41,100,000	41,100,000
			50,800,000
New York - 0.1%
FHLMC New York Hsg. Fin. Agcy. Rev. (Clinton Green North Hsg. Proj.) Series 2005 A, 0.24% 5/7/20, LOC Freddie Mac, VRDN
5/7/20	0.24 (b)(c)	31,655,000	31,655,000
FHLMC New York Hsg. Fin. Agcy. Rev. (Clinton Green South Hsg. Proj.) Series 2005 A, 0.24% 5/7/20, LOC Freddie Mac, VRDN
5/7/20	0.24 (b)(c)	15,900,000	15,900,000
FNMA New York City Hsg. Dev. Corp. Multi-family Rental Hsg. Rev. (155 West 21st Street Dev. Proj.) Series 2007 A, 0.24% 5/7/20, LOC Fannie Mae, VRDN
5/7/20	0.24 (b)(c)	12,200,000	12,200,000
FNMA New York City Hsg. Dev. Corp. Multi-family Rental Hsg. Rev. (90 West Street Proj.) Series 2006 A, 0.21% 5/7/20, LOC Fannie Mae, VRDN
5/7/20	0.21 (b)	17,000,000	17,000,000
FNMA New York Hsg. Fin. Agcy. Rev. (316 Eleventh Ave. Hsg. Proj.) Series 2007 A, 0.24% 5/7/20, LOC Fannie Mae, VRDN
5/7/20	0.24 (b)(c)	29,200,000	29,200,000
FNMA New York Hsg. Fin. Agcy. Rev. (600 West and 42nd St. Hsg. Proj.) Series 2007 A, 0.23% 5/7/20, LOC Fannie Mae, VRDN
5/7/20	0.23 (b)(c)	22,340,000	22,340,000
FNMA New York Hsg. Fin. Agcy. Rev. (750 Sixth Avenue Hsg. Proj.) Series 1999 A, 0.24% 5/7/20, LOC Fannie Mae, VRDN
5/7/20	0.24 (b)(c)	9,100,000	9,100,000
FNMA New York Hsg. Fin. Agcy. Rev. (Tribeca Park Proj.) Series 1997 A, 0.2% 5/7/20, LOC Fannie Mae, VRDN
5/7/20	0.20 (b)(c)	14,400,000	14,400,000
FNMA New York Hsg. Fin. Agcy. Rev. (West 23rd Street Hsg. Proj.) Series 2001 A, 0.17% 5/7/20, LOC Fannie Mae, VRDN
5/7/20	0.17 (b)(c)	6,500,000	6,500,000
FNMA New York Hsg. Fin. Agcy. Rev. Series 2009 A, 0.22% 5/7/20, LOC Fannie Mae, VRDN
5/7/20	0.22 (b)	20,900,000	20,900,000
			179,195,000
TOTAL VARIABLE RATE DEMAND NOTE
(Cost $229,995,000)			229,995,000

U.S. Government Agency Debt - 43.1%
Federal Agencies - 43.1%
Fannie Mae
6/5/20 to 5/4/22	0.05 to 0.68 (b)	13,882,115,000	13,877,697,324
Federal Farm Credit Bank
5/21/20 to 4/27/21	0.24 to 1.47 (b)	1,347,795,000	1,347,743,806
Federal Home Loan Bank
5/1/20 to 2/10/22	0.03 to 1.68 (b)	60,761,816,000	60,746,723,805
Freddie Mac
5/6/20 to 3/11/22	0.04 to 0.32 (b)(d)	5,193,900,000	5,193,861,990
TOTAL U.S. GOVERNMENT AGENCY DEBT
(Cost $81,166,026,925)			81,166,026,925

U.S. Government Agency Repurchase Agreement - 17.4%
	Maturity Amount	Value
In a joint trading account at:
0.05% dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations) #	$18,988,890,278	$18,988,866,000
0.05% dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations) #	58,935,082	58,935,000
With:
Barclays Bank PLC at 0.06%, dated:
4/27/20 due:
5/1/20 (Collateralized by U.S. Government Obligations valued at $321,302,142, 3.50% - 4.00%, 9/20/45 - 1/20/48)	315,002,100	315,000,000
5/4/20 (Collateralized by U.S. Government Obligations valued at $321,302,142, 3.50% - 4.00%, 10/20/43 - 5/20/49)	315,003,675	315,000,000
4/30/20 due 5/7/20 (Collateralized by U.S. Government Obligations valued at $321,300,536, 2.50% - 4.50%, 5/20/45 - 2/20/50)	315,003,675	315,000,000
BMO Harris Bank NA at:
0.06%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $52,530,088, 1.50% - 2.38%, 11/25/24 - 11/20/69)	51,000,085	51,000,000
0.11%, dated 4/2/20 due 5/4/20 (Collateralized by U.S. Government Obligations valued at $98,888,762, 1.12% - 1.17%, 1/20/49 - 4/20/49)	96,009,387	96,000,000
BNP Paribas, SA at:
0.07%, dated:
4/24/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $321,258,991, 0.00% - 6.50%, 5/15/20 - 7/20/67)	313,004,260	313,000,000
4/27/20 due 5/4/20 (Collateralized by U.S. Treasury Obligations valued at $112,914,157, 0.00% - 7.00%, 10/13/20 - 7/20/67)	110,001,497	110,000,000
0.63%, dated 3/9/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $573,852,544, 0.00% - 8.00%, 10/13/20 - 4/15/61)	558,859,320	558,000,000
CIBC Bank U.S.A. at:
0.09%, dated 4/22/20 due 5/7/20 (Collateralized by U.S. Government Obligations valued at $231,545,210, 3.00% - 5.50%, 7/14/32 - 6/20/64)	227,017,025	227,000,000
0.11%, dated 4/29/20 due 5/7/20 (Collateralized by U.S. Government Obligations valued at $136,680,835, 3.00% - 5.00%, 4/1/34 - 6/20/64)	134,012,283	134,000,000
Citibank NA at 0.05%, dated 4/28/20 due 5/5/20
(Collateralized by U.S. Government Obligations valued at $79,640,997, 0.00% - 8.13%, 10/9/20 - 9/15/65)	78,000,758	78,000,000
(Collateralized by U.S. Treasury Obligations valued at $481,958,501, 0.00% - 9.00%, 5/15/20 - 8/1/56)	471,004,579	471,000,000
Citigroup Global Capital Markets, Inc. at 0.05%, dated 4/28/20 due 5/5/20 (Collateralized by U.S. Government Obligations valued at $319,261,378, 1.50% - 6.00%, 9/30/21 - 10/1/48)	313,003,043	313,000,000
Deutsche Bank AG, New York at 0.06%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $211,150,390, 0.00% - 3.35%, 6/15/24 - 5/15/49)	205,000,342	205,000,000
Goldman Sachs & Co. at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $1,054,681,465, 3.00% - 5.50%, 7/20/26 - 1/15/55)	1,034,001,436	1,034,000,000
HSBC Securities, Inc. at 0.05%, dated 4/30/20 due 5/7/20 (Collateralized by U.S. Government Obligations valued at $321,300,446, 2.50% - 5.00%, 5/1/30 - 4/1/50)	315,003,063	315,000,000
ING Financial Markets LLC at:
0.16%, dated 4/29/20 due 5/29/20 (Collateralized by U.S. Government Obligations valued at $128,521,143, 4.00% - 4.50%, 9/1/43 - 7/1/48)	126,016,800	126,000,000
0.22%, dated 4/9/20 due 5/14/20
(Collateralized by U.S. Government Obligations valued at $130,577,553, 2.50% - 7.50%, 9/1/29 - 12/1/49)	128,027,378	128,000,000
(Collateralized by U.S. Treasury Obligations valued at $65,288,874, 0.00% - 2.00%, 9/15/20 - 2/15/22)	64,013,689	64,000,000
(Collateralized by U.S. Government Obligations valued at $130,577,553, 3.50% - 4.00%, 9/1/43 - 11/1/49)	128,027,378	128,000,000
0.24%, dated 4/13/20 due 5/18/20 (Collateralized by U.S. Treasury Obligations valued at $114,253,754, 2.00% - 5.00%, 2/15/22 - 11/20/48)	112,026,133	112,000,000
J.P. Morgan Securities, LLC at 0.05%, dated 4/28/20 due 5/5/20 (Collateralized by U.S. Government Obligations valued at $80,340,335, 0.05% - 4.08%, 3/15/31 - 9/25/52)	78,000,758	78,000,000
Mitsubishi UFJ Securities (U.S.A.), Inc. at:
0.16%, dated:
4/23/20 due 6/22/20 (Collateralized by U.S. Government Obligations valued at $275,409,792, 2.00% - 5.54%, 1/1/24 - 5/1/50)	270,072,000	270,000,000
4/24/20 due 6/23/20 (Collateralized by U.S. Government Obligations valued at $225,427,013, 2.27% - 5.00%, 5/1/25 - 6/15/60)	221,058,933	221,000,000
4/29/20 due 6/26/20 (Collateralized by U.S. Government Obligations valued at $208,081,850, 3.00% - 5.00%, 2/1/33 - 4/1/50)	204,052,587	204,000,000
0.17%, dated 4/29/20 due 6/30/20 (Collateralized by U.S. Government Obligations valued at $208,081,965, 2.50% - 6.00%, 1/20/24 - 5/1/50)	204,059,727	204,000,000
0.19%, dated:
4/14/20 due 5/7/20 (Collateralized by U.S. Government Obligations valued at $97,928,786, 2.50% - 3.00%, 2/1/50 - 4/1/50)	96,019,253	96,000,000
4/20/20 due 6/19/20 (Collateralized by U.S. Government Obligations valued at $162,189,415, 2.50% - 4.55%, 2/1/27 - 3/1/50)	159,050,350	159,000,000
Morgan Stanley & Co., LLC at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $593,641,191, 1.60% - 8.50%, 1/1/21 - 8/1/56)	582,000,808	582,000,000
RBC Dominion Securities at:
0.06%, dated 4/21/20 due 5/5/20 (Collateralized by U.S. Government Obligations valued at $161,242,251, 0.50% - 5.00%, 7/31/22 - 2/20/50)	158,003,687	158,000,000
0.07%, dated 4/23/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $970,966,310, 0.00% - 7.13%, 5/31/20 - 12/20/49)	951,025,888	951,000,000
RBC Financial Group at:
0.06%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $583,440,973, 2.50% - 6.00%, 7/1/23 - 5/1/58)	572,000,953	572,000,000
0.18%, dated:
3/18/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $2,379,715,761, 0.94% - 6.84%, 4/1/24 - 8/25/59)	2,329,512,380	2,329,000,000
3/19/20 due 5/4/20 (Collateralized by U.S. Government Obligations valued at $400,287,204, 0.79% - 7.00%, 7/1/26 - 5/1/58)	392,090,160	392,000,000
Sumitomo Mitsui Trust Bank Ltd. at 0.23%, dated:
4/21/20 due 5/7/20 (Collateralized by U.S. Government Obligations valued at $111,858,345, 2.00% - 3.00%, 1/15/21 - 1/1/47)	109,515,838	109,496,250
4/23/20 due 5/7/20 (Collateralized by U.S. Government Obligations valued at $208,602,105, 2.00% - 4.00%, 1/15/21 - 11/1/48)	204,036,493	204,000,000
4/24/20 due 5/7/20 (Collateralized by U.S. Government Obligations valued at $121,938,238, 3.50%, 1/1/48)	119,021,288	119,000,000
4/28/20 due 5/7/20 (Collateralized by U.S. Government Obligations valued at $204,227,566, 2.00% - 3.00%, 1/15/21 - 10/20/46)	200,005,388	199,987,500
TD Securities (U.S.A.) at 0.05%, dated 4/28/20 due 5/5/20 (Collateralized by U.S. Government Obligations valued at $800,703,337, 3.00% - 5.00%, 3/20/41 - 11/1/49)	785,007,632	785,000,000
Wells Fargo Securities, LLC at 0.06%, dated 4/30/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $649,922,588, 2.38% - 7.63%, 11/15/24 - 11/15/49)	631,007,362	631,000,000
TOTAL U.S. GOVERNMENT AGENCY REPURCHASE AGREEMENT
(Cost $32,720,284,750)		32,720,284,750

U.S. Treasury Repurchase Agreement - 22.4%
With:
Barclays Bank PLC at 0.04%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $3,224,357,274, 0.50% - 3.38%, 1/15/21 - 11/15/48)	3,152,003,502	3,152,000,000
BMO Harris Bank NA at:
0.09%, dated:
4/17/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $218,287,697, 0.50% - 2.63%, 6/30/23 - 4/30/27)	214,010,700	214,000,000
4/23/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $86,701,795, 1.13% - 1.38%, 7/31/21 - 8/31/23)	85,007,013	85,000,000
1.6%, dated 2/10/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $123,871,359, 1.13% - 3.88%, 7/31/21 - 11/15/48)	121,489,378	121,000,000
BNP Paribas, SA at:
0.04%, dated:
4/28/20 due 5/5/20 (Collateralized by U.S. Treasury Obligations valued at $868,199,636, 0.00% - 7.63%, 10/22/20 - 8/15/49)	849,006,603	849,000,000
4/30/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $293,276,463, 0.17% - 4.75%, 7/31/20 - 2/15/50)	286,002,224	286,000,000
0.06%, dated:
4/24/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $649,683,229, 0.00% - 6.25%, 2/15/21 - 11/15/48)	636,007,420	636,000,000
4/27/20 due 5/4/20 (Collateralized by U.S. Treasury Obligations valued at $347,389,647, 0.00% - 7.50%, 8/15/20 - 2/15/50)	339,003,955	339,000,000
0.17%, dated 3/18/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $405,030,575, 0.00% - 7.13%, 7/31/20 - 8/15/49)	397,114,358	397,000,000
0.46%, dated 3/10/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $1,000,539,435, 0.00% - 7.63%, 7/31/20 - 11/15/49)	978,123,550	977,000,000
0.5%, dated 3/11/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $1,233,011,190, 0.26% - 7.63%, 4/30/21 - 2/15/50)	1,204,503,750	1,203,000,000
0.62%, dated 3/6/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $714,556,499, 0.00% - 8.75%, 7/31/20 - 8/15/49)	700,095,488	699,000,000
1.61%, dated:
2/18/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $558,063,841, 0.17% - 6.75%, 7/31/20 - 11/15/47)	544,181,550	542,000,000
2/19/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $143,844,473, 0.43% - 7.63%, 10/31/21 - 11/15/49)	140,563,500	140,000,000
CIBC Bank U.S.A. at 0.09%, dated 4/30/20 due 5/7/20
(Collateralized by U.S. Treasury Obligations valued at $782,342,044, 0.50% - 3.13%, 1/15/22 - 5/15/48)	767,080,535	767,000,000
(Collateralized by U.S. Treasury Obligations valued at $153,000,422, 1.63% - 2.88%, 1/31/23 - 8/15/28)	150,010,875	150,000,000
Commerz Markets LLC at:
0.04%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $2,297,367,347, 0.00% - 3.13%, 1/28/21 - 8/15/49)	2,251,002,501	2,251,000,000
0.05%, dated 4/28/20 due 5/5/20 (Collateralized by U.S. Treasury Obligations valued at $873,123,672, 1.38% - 2.88%, 8/31/22 - 8/15/28)	856,008,322	856,000,000
0.06%, dated:
4/29/20 due 5/6/20 (Collateralized by U.S. Treasury Obligations valued at $657,308,188, 0.00% - 3.00%, 7/30/20 - 8/15/49)	644,007,513	644,000,000
4/30/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $656,184,605, 0.50% - 3.13%, 12/15/22 - 8/15/49)	643,007,502	643,000,000
Credit AG at:
0.09%, dated:
4/2/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $292,761,326, 1.63%, 9/30/26)	287,020,808	287,000,000
4/22/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $289,686,616, 1.63% - 2.88%, 10/31/20 - 9/30/26)	284,021,300	284,000,000
4/23/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $581,588,035, 1.50% - 3.63%, 6/15/20 - 2/15/44)	567,046,778	567,000,000
0.11%, dated 4/3/20 due 5/4/20 (Collateralized by U.S. Treasury Obligations valued at $292,765,118, 1.63% - 2.88%, 11/30/25 - 9/30/26)	287,027,185	287,000,000
0.13%, dated 4/20/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $289,691,608, 2.88%, 10/31/20)	284,030,767	284,000,000
Credit Agricole CIB at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $345,995,200, 1.50% - 2.38%, 8/15/24 - 2/15/30)	339,000,471	339,000,000
Deutsche Bank AG, New York at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $989,411,813, 1.13% - 4.25%, 11/15/20 - 11/15/47)	967,001,343	967,000,000
Deutsche Bank Securities, Inc. at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $29,580,131, 1.88% - 2.88%, 4/30/22 - 7/31/25)	29,000,040	29,000,000
DNB Bank ASA at 0.04%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $828,801,989, 1.25% - 2.75%, 1/15/23 - 2/15/28)	788,000,876	788,000,000
Fixed Income Clearing Corp. - BNYM at:
0.04%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $2,251,140,055, 1.50% - 2.88%, 2/28/22 - 5/15/28)	2,207,002,452	2,207,000,000
0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $742,560,068, 1.50% - 1.75%, 6/30/22 - 8/15/26)	728,001,011	728,000,000
Fixed Income Clearing Corp. - SSB at 0.04%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $3,043,765,460, 1.38% - 2.00%, 9/15/22 - 12/15/22)	2,984,003,316	2,984,000,000
HSBC Securities, Inc. at 0.04%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $430,027,049, 2.88%, 5/31/25)	417,000,463	417,000,000
ING Financial Markets LLC at 0.04%, dated 4/30/20 due:
5/1/20 (Collateralized by U.S. Treasury Obligations valued at $862,934,269, 1.50% - 2.88%, 10/31/21 - 5/31/25)	846,000,940	846,000,000
5/7/20 (Collateralized by U.S. Treasury Obligations valued at $88,740,176, 0.00% - 4.63%, 5/31/20 - 11/15/46)	87,000,677	87,000,000
Lloyds Bank Corp. Markets PLC at:
0.2%, dated 4/3/20 due 5/4/20 (Collateralized by U.S. Treasury Obligations valued at $146,966,756, 1.88% - 2.75%, 2/28/25 - 7/31/26)	144,024,800	144,000,000
0.27%, dated 4/3/20 due 5/4/20 (Collateralized by U.S. Treasury Obligations valued at $146,973,438, 1.88% - 2.75%, 2/28/25 - 7/31/26)	144,033,480	144,000,000
Lloyds Bank PLC at:
0.14%, dated 5/4/20 due 6/4/20(e)	282,033,997	282,000,000
0.15%, dated 4/6/20 due 5/6/20 (Collateralized by U.S. Treasury Obligations valued at $145,943,603, 1.63% - 6.00%, 5/15/21 - 9/30/26)	143,017,875	143,000,000
0.18%, dated:
4/21/20 due 5/21/20 (Collateralized by U.S. Treasury Obligations valued at $145,945,622, 1.75% - 6.00%, 11/15/20 - 2/15/26)	143,021,450	143,000,000
4/22/20 due 5/22/20 (Collateralized by U.S. Treasury Obligations valued at $145,901,765, 1.88% - 6.00%, 2/28/22 - 2/15/26)	143,021,450	143,000,000
0.27%, dated 4/2/20 due 5/4/20 (Collateralized by U.S. Treasury Obligations valued at $291,796,362, 1.38% - 6.00%, 2/15/26 - 8/31/26)	286,068,640	286,000,000
0.54%, dated 3/12/20 due 6/12/20 (Collateralized by U.S. Treasury Obligations valued at $153,129,485, 1.63% - 6.00%, 3/15/22 - 9/30/26)	150,207,000	150,000,000
0.65%, dated 3/16/20 due 5/15/20 (Collateralized by U.S. Treasury Obligations valued at $210,621,661, 1.63% - 6.75%, 11/15/22 - 8/15/26)	206,223,167	206,000,000
0.83%, dated 3/9/20 due 6/9/20 (Collateralized by U.S. Treasury Obligations valued at $154,388,257, 6.00%, 2/15/26)	151,320,288	151,000,000
1.63%, dated:
2/18/20 due 5/18/20 (Collateralized by U.S. Treasury Obligations valued at $154,476,603, 2.63% - 6.75%, 5/15/21 - 8/15/26)	151,615,325	151,000,000
2/19/20 due 5/19/20 (Collateralized by U.S. Treasury Obligations valued at $108,591,541, 6.00%, 2/15/26)	106,431,950	106,000,000
2/21/20 due 5/21/20 (Collateralized by U.S. Treasury Obligations valued at $341,697,557, 1.63% - 6.00%, 5/15/21 - 9/30/26)	335,361,050	334,000,000
Mizuho Bank, Ltd. at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $432,188,511, 2.38%, 5/15/29)	423,000,588	423,000,000
Mizuho Securities U.S.A., Inc. at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $851,498,445, 1.75% - 3.00%, 2/28/22 - 8/15/28)	835,001,160	835,000,000
MUFG Securities (Canada), Ltd. at 0.05%, dated 4/24/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $216,242,212, 1.38% - 3.13%, 8/15/21 - 11/15/28)	212,002,061	212,000,000
MUFG Securities EMEA PLC at:
0.04%, dated 4/29/20 due 5/6/20 (Collateralized by U.S. Treasury Obligations valued at $174,372,092, 1.38% - 2.75%, 1/31/22 - 12/31/26)	171,001,330	171,000,000
0.05%, dated:
4/23/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $159,078,937, 2.13% - 3.13%, 3/31/24 - 8/15/44)	156,001,733	156,000,000
4/28/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $59,143,126, 2.13% - 3.63%, 2/15/21 - 8/15/44)	58,000,242	58,000,000
4/29/20 due 5/4/20 (Collateralized by U.S. Treasury Obligations valued at $253,887,620, 2.13% - 3.00%, 3/31/24 - 2/15/47)	249,001,729	249,000,000
4/30/20 due 5/1/20
(Collateralized by U.S. Treasury Obligations valued at $575,289,803, 0.63% - 1.13%, 2/28/25 - 3/31/27)	564,000,783	564,000,000
(Collateralized by U.S. Treasury Obligations valued at $651,573,909, 1.75% - 2.75%, 5/31/22 - 3/31/25)	639,000,888	639,000,000
5/1/20 due 5/7/20(e)	404,005,611	404,000,000
0.06%, dated 4/28/20 due 5/5/20 (Collateralized by U.S. Treasury Obligations valued at $497,629,003, 1.50% - 2.75%, 10/31/21 - 5/15/26)	488,005,693	488,000,000
0.07%, dated:
4/23/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $383,424,972, 1.13% - 3.13%, 6/30/21 - 8/15/44)	376,010,236	376,000,000
4/24/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $262,988,758, 1.13% - 3.13%, 11/30/20 - 8/15/44)	257,903,510	257,900,000
4/30/20 due:
5/4/20 (Collateralized by U.S. Treasury Obligations valued at $437,453,096, 1.63% - 2.75%, 6/30/25 - 5/15/26)	429,003,337	429,000,000
5/7/20 (Collateralized by U.S. Treasury Obligations valued at $161,014,708, 2.63% - 3.13%, 2/15/29 - 8/15/44)	157,902,149	157,900,000
5/1/20 due 5/7/20(e)	133,004,914	133,000,000
0.08%, dated:
4/27/20 due 5/4/20 (Collateralized by U.S. Treasury Obligations valued at $325,291,229, 1.63% - 2.88%, 4/15/22 - 8/15/28)	319,004,962	319,000,000
4/30/20 due 5/7/20
(Collateralized by U.S. Treasury Obligations valued at $287,572,604, 1.38% - 2.75%, 5/31/21 - 11/15/23)	282,009,400	282,000,000
(Collateralized by U.S. Treasury Obligations valued at $295,716,689, 1.13% - 2.63%, 5/31/20 - 9/30/26)	290,007,733	290,000,000
Natixis SA at 0.04%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $1,755,920,300, 0.00% - 6.38%, 5/31/20 - 5/15/49)	1,719,001,910	1,719,000,000
Norinchukin Bank at:
0.18%, dated:
4/16/20 due 5/18/20 (Collateralized by U.S. Treasury Obligations valued at $146,890,400, 1.50%, 8/15/26)	144,023,040	144,000,000
4/17/20 due 5/20/20 (Collateralized by U.S. Treasury Obligations valued at $145,869,600, 2.63%, 11/15/20)	143,023,595	143,000,000
0.57%, dated:
3/10/20 due 6/10/20 (Collateralized by U.S. Treasury Obligations valued at $105,144,897, 2.00%, 11/15/26)	103,150,037	103,000,000
3/12/20 due 6/11/20 (Collateralized by U.S. Treasury Obligations valued at $242,948,451, 2.63%, 11/15/20)	238,342,918	238,000,000
0.85%, dated 3/5/20 due 6/5/20 (Collateralized by U.S. Treasury Obligations valued at $230,824,874, 2.38%, 5/15/27)	226,490,922	226,000,000
1.56%, dated 2/27/20 due 5/28/20 (Collateralized by U.S. Treasury Obligations valued at $76,708,885, 1.50%, 8/15/26)	75,295,750	75,000,000
1.64%, dated 2/25/20 due 5/26/20 (Collateralized by U.S. Treasury Obligations valued at $155,499,201, 2.63%, 11/15/20)	152,630,124	152,000,000
1.66%, dated:
2/18/20 due 5/19/20 (Collateralized by U.S. Treasury Obligations valued at $46,052,475, 2.00%, 11/15/26)	45,188,825	45,000,000
2/19/20 due 5/19/20 (Collateralized by U.S. Treasury Obligations valued at $77,773,871, 2.00%, 11/15/26)	76,315,400	76,000,000
2/21/20 due 5/22/20 (Collateralized by U.S. Treasury Obligations valued at $225,114,102, 1.50% - 2.00%, 8/15/26 - 11/15/26)	220,923,144	220,000,000
RBC Dominion Securities at:
0.05%, dated 4/21/20 due 5/5/20 (Collateralized by U.S. Treasury Obligations valued at $1,010,474,333, 0.00% - 7.13%, 5/31/20 - 11/15/49)	990,019,250	990,000,000
0.87%, dated 3/5/20 due 5/5/20 (Collateralized by U.S. Treasury Obligations valued at $315,748,474, 1.25% - 7.13%, 5/31/20 - 5/15/49)	308,454,043	308,000,000
RBC Financial Group at 0.16%, dated 3/19/20 due 5/4/20 (Collateralized by U.S. Treasury Obligations valued at $432,311,490, 0.25% - 7.63%, 2/15/21 - 11/15/46)	423,086,480	423,000,000
RBS Securities, Inc. at 0.06%, dated 4/30/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $220,281,156, 0.00% - 3.00%, 1/28/21 - 11/15/45)	215,002,508	215,000,000
SMBC Nikko Securities America, Inc. at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $785,196,795, 2.63% - 2.88%, 10/31/20 - 8/15/28)	770,001,069	770,000,000
Societe Generale at:
0.04%, dated 4/28/20 due 5/5/20 (Collateralized by U.S. Treasury Obligations valued at $294,049,422, 1.38% - 4.75%, 10/31/20 - 8/15/48)	287,002,232	287,000,000
0.05%, dated:
4/29/20 due 5/6/20 (Collateralized by U.S. Treasury Obligations valued at $289,073,601, 1.38% - 4.75%, 8/15/20 - 8/15/49)	282,002,742	282,000,000
4/30/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $569,214,098, 0.13% - 8.75%, 5/15/20 - 8/15/48)	558,005,425	558,000,000
TD Securities (U.S.A.) at 0.04%, dated 4/28/20 due 5/5/20 (Collateralized by U.S. Treasury Obligations valued at $314,752,959, 2.25% - 8.00%, 11/15/21 - 8/15/49)	307,002,388	307,000,000
TOTAL U.S. TREASURY REPURCHASE AGREEMENT
(Cost $42,159,800,000)		42,159,800,000
TOTAL INVESTMENT IN SECURITIES - 101.9%
(Cost $191,834,495,695)		191,834,495,695
NET OTHER ASSETS (LIABILITIES) - (1.9)%		(3,539,646,015)
NET ASSETS - 100%		$188,294,849,680

Security Type Abbreviations

VRDN – VARIABLE RATE DEMAND NOTE (A debt instrument that is payable upon demand, either daily, weekly or monthly)

Legend

(a) Yield represents either the annualized yield at the date of purchase, or the stated coupon rate, or, for floating and adjustable rate securities, the rate at period end.

(b) Coupon rates for floating and adjustable rate securities reflect the rates in effect at period end.

(d) Coupon is indexed to a floating interest rate which may be multiplied by a specified factor and/or subject to caps or floors.

(e) Represents a forward settling transaction and therefore no collateral securities had been allocated as of period end. The agreement contemplated the delivery of U.S. Treasury Obligations as collateral on settlement date.

Investment Valuation

Other Information

# Additional information on each counterparty to the repurchase agreement is as follows:

Repurchase Agreement / Counterparty	Value
$18,988,866,000 due 5/01/20 at 0.05%
BNP Paribas, S.A.	$97,408,000
BNY Mellon Capital Markets LLC	1,291,452,000
Bank of America, N.A.	930,437,000
Bank of America Securities, Inc.	1,085,265,000
Citibank, N.A.	258,455,000
Citigroup Global Markets, Inc.	566,374,000
Credit Agricole CIB New York Branch	1,183,210,000
HSBC Securities (USA), Inc.	2,237,362,000
ING Financial Markets LLC	98,019,000
J.P. Morgan Securities LLC	2,283,809,000
Mitsubishi UFJ Securities Holdings Ltd.	1,993,750,000
Mitsubishi UFJ Securities (USA)	107,759,000
Mizuho Securities USA, Inc.	465,220,000
Nomura Securities International	1,566,994,000
Societe Generale (PARIS)	594,704,000
Sumitomo Mitsu Banking Corp. NY	877,896,000
Sumitomo Mitsui Banking Corp.	3,001,838,000
Wells Fargo Securities LLC	348,914,000
	$18,988,866,000
$58,935,000 due 5/01/20 at 0.05%
Citibank, N.A.	$9,216,000
Credit Agricole CIB New York Branch	36,992,000
Mizuho Securities USA, Inc.	12,727,000
	$58,935,000

See accompanying notes which are an integral part of the financial statements.

Financial Statements

Statement of Assets and Liabilities

		April 30, 2020
Assets
Investment in securities, at value (including repurchase agreements of $74,880,084,750) — See accompanying schedule: Unaffiliated issuers (cost $191,834,495,695)		$191,834,495,695
Cash		1,502
Receivable for investments sold		246,004,350
Receivable for fund shares sold		966,788,360
Interest receivable		87,451,034
Prepaid expenses		54,664
Receivable from investment adviser for expense reductions		632,517
Other receivables		657,189
Total assets		193,136,085,311
Liabilities
Payable for investments purchased	$3,833,043,268
Payable for fund shares redeemed	938,755,627
Distributions payable	269,251
Accrued management fee	39,045,764
Distribution and service plan fees payable	1,765
Other affiliated payables	20,081,340
Other payables and accrued expenses	10,038,616
Total liabilities		4,841,235,631
Net Assets		$188,294,849,680
Net Assets consist of:
Paid in capital		$188,294,666,514
Total accumulated earnings (loss)		183,166
Net Assets		$188,294,849,680
Net Asset Value and Maximum Offering Price
Capital Reserves Class:
Net Asset Value, offering price and redemption price per share ($7,470,316,312 ÷ 7,468,156,582 shares)		$1.00
Daily Money Class:
Net Asset Value, offering price and redemption price per share ($7,835,091,339 ÷ 7,833,054,758 shares)		$1.00
Advisor M Class:
Net Asset Value, offering price and redemption price per share ($126,268,822 ÷ 126,271,599 shares)		$1.00
Fidelity Government Money Market Fund:
Net Asset Value, offering price and redemption price per share ($165,823,961,907 ÷ 165,820,273,898 shares)		$1.00
Premium Class:
Net Asset Value, offering price and redemption price per share ($5,726,123,972 ÷ 5,724,698,431 shares)		$1.00
Class K6:
Net Asset Value, offering price and redemption price per share ($1,313,087,328 ÷ 1,313,100,287 shares)		$1.00

See accompanying notes which are an integral part of the financial statements.

Statement of Operations

		Year ended April 30, 2020
Investment Income
Interest		$2,548,007,579
Expenses
Management fee	$364,049,908
Transfer agent fees	227,569,876
Distribution and service plan fees	50,291,370
Accounting fees and expenses	3,725,779
Custodian fees and expenses	1,027,159
Independent trustees' fees and expenses	521,907
Registration fees	16,337,090
Audit	48,782
Legal	165,640
Interest	3,706,825
Miscellaneous	446,640
Total expenses before reductions	667,890,976
Expense reductions	(14,466,731)
Total expenses after reductions		653,424,245
Net investment income (loss)		1,894,583,334
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment securities:
Unaffiliated issuers		1,249,552
Total net realized gain (loss)		1,249,552
Net increase in net assets resulting from operations		$1,895,832,886

See accompanying notes which are an integral part of the financial statements.

Statement of Changes in Net Assets

	Year ended April 30, 2020	Year ended April 30, 2019
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$1,894,583,334	$1,974,174,690
Net realized gain (loss)	1,249,552	397,770
Net increase in net assets resulting from operations	1,895,832,886	1,974,572,460
Distributions to shareholders	(1,894,622,301)	(1,974,138,272)
Share transactions - net increase (decrease)	66,219,398,590	17,585,365,642
Total increase (decrease) in net assets	66,220,609,175	17,585,799,830
Net Assets
Beginning of period	122,074,240,505	104,488,440,675
End of period	$188,294,849,680	$122,074,240,505

See accompanying notes which are an integral part of the financial statements.

Financial Highlights

Fidelity Government Money Market Fund Capital Reserves Class

Years ended April 30,	2020	2019	2018	2017	2016
Selected Per–Share Data
Net asset value, beginning of period	$1.00	$1.00	$1.00	$1.00	$1.00
Income from Investment Operations
Net investment income (loss)	.009	.012	.003	–^A	–^A
Net realized and unrealized gain (loss)^A	–	–	–	–	–
Total from investment operations	.009	.012	.003	–^A	–^A
Distributions from net investment income	(.009)	(.012)	(.003)	–^A	–^A
Total distributions	(.009)	(.012)	(.003)	–^A	–^A
Net asset value, end of period	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return^B,^C	.94%	1.26%	.27%	.01%	.01%
Ratios to Average Net Assets^D
Expenses before reductions	.97%	.96%	.96%	.97%	.99%
Expenses net of fee waivers, if any	.89%	.95%	.93%	.53%	.32%
Expenses net of all reductions	.89%	.95%	.93%	.53%	.32%
Net investment income (loss)	.87%	1.26%	.26%	.02%	.01%
Supplemental Data
Net assets, end of period (000 omitted)	$7,470,316	$6,491,629	$8,466,153	$10,328,334	$10,396,942

^A Amount represents less than $.0005 per share.

^B Total returns for periods of less than one year are not annualized.

^C Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

See accompanying notes which are an integral part of the financial statements.

Fidelity Government Money Market Fund Daily Money Class

Years ended April 30,	2020	2019	2018	2017	2016
Selected Per–Share Data
Net asset value, beginning of period	$1.00	$1.00	$1.00	$1.00	$1.00
Income from Investment Operations
Net investment income (loss)	.012	.015	.005	–^A	–^A
Net realized and unrealized gain (loss)^A	–	–	–	–	–
Total from investment operations	.012	.015	.005	–^A	–^A
Distributions from net investment income	(.012)	(.015)	(.005)	–^A	–^A
Total distributions	(.012)	(.015)	(.005)	–^A	–^A
Net asset value, end of period	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return^B,^C	1.16%	1.51%	.50%	.02%	.01%
Ratios to Average Net Assets^D
Expenses before reductions	.72%	.71%	.71%	.72%	.74%
Expenses net of fee waivers, if any	.67%	.70%	.70%	.52%	.32%
Expenses net of all reductions	.67%	.70%	.70%	.52%	.32%
Net investment income (loss)	1.08%	1.51%	.49%	.03%	.01%
Supplemental Data
Net assets, end of period (000 omitted)	$7,835,091	$6,038,320	$6,913,180	$8,145,306	$8,838,747

^A Amount represents less than $.0005 per share.

^B Total returns for periods of less than one year are not annualized.

^C Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

See accompanying notes which are an integral part of the financial statements.

Fidelity Government Money Market Fund Advisor M Class

Years ended April 30,	2020	2019	2018 ^A
Selected Per–Share Data
Net asset value, beginning of period	$1.00	$1.00	$1.00
Income from Investment Operations
Net investment income (loss)	.012	.015	.005
Net realized and unrealized gain (loss)^B	–	–	–
Total from investment operations	.012	.015	.005
Distributions from net investment income	(.012)	(.015)	(.005)
Total distributions	(.012)	(.015)	(.005)
Net asset value, end of period	$1.00	$1.00	$1.00
Total Return^C,^D	1.17%	1.52%	.48%
Ratios to Average Net Assets^E
Expenses before reductions	.72%	.71%	.72%^F
Expenses net of fee waivers, if any	.65%	.70%	.70%^F
Expenses net of all reductions	.64%	.69%	.69%^F
Net investment income (loss)	1.12%	1.53%	.71%^F
Supplemental Data
Net assets, end of period (000 omitted)	$126,269	$50,630	$29,889

^A For the period July 6, 2017 (commencement of sale of shares) to April 30, 2018.

^B Amount represents less than $.0005 per share.

^C Total returns for periods of less than one year are not annualized.

^D Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^E Expense ratios reflect operating expenses of the class. Expenses before reductions do not reflect amounts reimbursed or waived or reductions from expense offset arrangements and do not represent the amount paid by the class during periods when reimbursements, waivers or reductions occur. Expense ratios before reductions for start-up periods may not be representative of longer-term operating periods. Expenses net of fee waivers reflect expenses after reimbursement and waivers but prior to reductions from expense offset arrangements. Expenses net of all reductions represent the net expenses paid by the class.

^F Annualized

See accompanying notes which are an integral part of the financial statements.

Fidelity Government Money Market Fund

Years ended April 30,	2020	2019	2018	2017	2016
Selected Per–Share Data
Net asset value, beginning of period	$1.00	$1.00	$1.00	$1.00	$1.00
Income from Investment Operations
Net investment income (loss)	.014	.018	.008	.001	–^A
Net realized and unrealized gain (loss)^A	–	–	–	–	–
Total from investment operations	.014	.018	.008	.001	–^A
Distributions from net investment income	(.014)	(.018)	(.008)	(.001)	–^A
Total distributions	(.014)	(.018)	(.008)	(.001)	–^A
Net asset value, end of period	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return^B	1.42%	1.79%	.78%	.12%	.01%
Ratios to Average Net Assets^C
Expenses before reductions	.42%	.42%	.42%	.42%	.42%
Expenses net of fee waivers, if any	.42%	.42%	.42%	.42%	.26%
Expenses net of all reductions	.42%	.42%	.42%	.42%	.26%
Net investment income (loss)	1.33%	1.79%	.81%	.14%	.01%
Supplemental Data
Net assets, end of period (000 omitted)	$165,823,962	$104,973,598	$86,131,220	$63,580,065	$31,943,681

^A Amount represents less than $.0005 per share.

^B Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

See accompanying notes which are an integral part of the financial statements.

Fidelity Government Money Market Fund Premium Class

Years ended April 30,	2020	2019	2018	2017	2016
Selected Per–Share Data
Net asset value, beginning of period	$1.00	$1.00	$1.00	$1.00	$1.00
Income from Investment Operations
Net investment income (loss)	.015	.019	.009	.002	–^A
Net realized and unrealized gain (loss)^A	–	–	–	–	–
Total from investment operations	.015	.019	.009	.002	–^A
Distributions from net investment income	(.015)	(.019)	(.009)	(.002)	–^A
Total distributions	(.015)	(.019)	(.009)	(.002)	–^A
Net asset value, end of period	$1.00	$1.00	$1.00	$1.00	$1.00
Total Return^B,^C	1.52%	1.90%	.89%	.22%	.03%
Ratios to Average Net Assets^D
Expenses before reductions	.37%	.36%	.36%	.37%	.38%
Expenses net of fee waivers, if any	.32%	.32%	.32%	.32%	.29%
Expenses net of all reductions	.32%	.32%	.32%	.32%	.29%
Net investment income (loss)	1.43%	1.89%	.89%	.24%	.07%
Supplemental Data
Net assets, end of period (000 omitted)	$5,726,124	$4,115,468	$2,901,645	$2,444,687	$2,031,894

^A Amount represents less than $.0005 per share.

^B Total returns for periods of less than one year are not annualized.

^C Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

See accompanying notes which are an integral part of the financial statements.

Fidelity Government Money Market Fund Class K6

Years ended April 30,	2020	2019	2018 ^A
Selected Per–Share Data
Net asset value, beginning of period	$1.00	$1.00	$1.00
Income from Investment Operations
Net investment income (loss)	.016	.019	.003
Net realized and unrealized gain (loss)^B	–	–	–
Total from investment operations	.016	.019	.003
Distributions from net investment income	(.016)	(.019)	(.003)
Total distributions	(.016)	(.019)	(.003)
Net asset value, end of period	$1.00	$1.00	$1.00
Total Return^C,^D	1.59%	1.97%	.34%
Ratios to Average Net Assets^E
Expenses before reductions	.28%	.27%	.27%^F
Expenses net of fee waivers, if any	.25%	.25%	.25%^F
Expenses net of all reductions	.25%	.25%	.25%^F
Net investment income (loss)	1.50%	1.96%	1.47%^F
Supplemental Data
Net assets, end of period (000 omitted)	$1,313,087	$404,595	$46,354

^A For the period January 24, 2018 (commencement of sale of shares) to April 30, 2018.

^B Amount represents less than $.0005 per share.

^C Total returns for periods of less than one year are not annualized.

^D Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^F Annualized

See accompanying notes which are an integral part of the financial statements.

Notes to Financial Statements

For the period ended April 30, 2020

1. Organization.

Fidelity Government Money Market Fund (the Fund) is a fund of Fidelity Hereford Street Trust (the Trust) and is authorized to issue an unlimited number of shares. The Trust is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company organized as a Delaware statutory trust. The Fund offers Capital Reserves Class, Daily Money Class, Advisor M Class, Fidelity Government Money Market Fund, Premium Class and Class K6 shares, each of which has equal rights as to assets and voting privileges. Each class has exclusive voting rights with respect to matters that affect that class.

Effective January 1, 2020:

Broker-dealer Fidelity Distributors Corporation merged with and into Fidelity Investments Institutional Services Company, Inc. ("FIISC"). FIISC was then redomiciled from Massachusetts to Delaware, changed its corporate structure from a corporation to a limited liability company, and changed its name to "Fidelity Distributors Company LLC".

2. Significant Accounting Policies.

Investment Valuation. The Fund categorizes the inputs to valuation techniques used to value its investments into a disclosure hierarchy consisting of three levels as shown below:

Level 1 – quoted prices in active markets for identical investments
Level 2 – other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, etc.)
Level 3 – unobservable inputs (including the Fund's own assumptions based on the best information available)

Class Allocations and Expenses. Investment income, realized and unrealized capital gains and losses, common expenses of the Fund, and certain fund-level expense reductions, if any, are allocated daily on a pro-rata basis to each class based on the relative net assets of each class to the total net assets of the Fund. Each class differs with respect to transfer agent and distribution and service plan fees incurred. Certain expense reductions may also differ by class. For the reporting period, the allocated portion of income and expenses to each class as a percent of its average net assets may vary due to the timing of recording these transactions in relation to fluctuating net assets of the classes. Expenses directly attributable to a fund are charged to that fund. Expenses attributable to more than one fund are allocated among the respective funds on the basis of relative net assets or other appropriate methods. Expense estimates are accrued in the period to which they relate and adjustments are made when actual amounts are known.

Deferred Trustee Compensation. Under a Deferred Compensation Plan (the Plan) for the Fund, certain independent Trustees have elected to defer receipt of a portion of their annual compensation. Deferred amounts are invested in a cross-section of Fidelity funds, are marked-to-market and remain in the Fund until distributed in accordance with the Plan. The investment of deferred amounts and the offsetting payable to the Trustees of $657,089 are included in the accompanying Statement of Assets and Liabilities in other receivables and other payables and accrued expenses, respectively.

Distributions are declared and recorded daily and paid monthly from net investment income. Distributions from realized gains, if any, are declared and recorded on the ex-dividend date. Income and capital gain distributions are declared separately for each class. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from GAAP. In addition, the Fund claimed a portion of the payment made to redeeming shareholders as a distribution for income tax purposes.

Book-tax differences are primarily due to deferred trustees compensation and losses deferred due to wash sales.

As of period end, the cost and unrealized appreciation (depreciation) in securities for federal income tax purposes were as follows:

Gross unrealized appreciation	$–
Gross unrealized depreciation	–
Net unrealized appreciation (depreciation)	$–
Tax Cost	$191,834,495,695

The tax-based components of distributable earnings as of period end were as follows:

Undistributed ordinary income

$842,312

The tax character of distributions paid was as follows:

	April 30, 2020	April 30, 2019
Ordinary Income	$1,894,622,301	$ 1,974,138,272

Repurchase Agreements. Pursuant to an Exemptive Order issued by the Securities and Exchange Commission (the SEC), the Fund along with other registered investment companies having management contracts with Fidelity Management & Research Company LLC (FMR), or other affiliated entities of FMR, are permitted to transfer uninvested cash balances into joint trading accounts which are then invested in repurchase agreements. The Fund may also invest directly with institutions in repurchase agreements. Repurchase agreements may be collateralized by cash or government securities. Upon settlement date, collateral is held in segregated accounts with custodian banks and may be obtained in the event of a default of the counterparty. The Fund monitors, on a daily basis, the value of the collateral to ensure it is at least equal to the principal amount of the repurchase agreement (including accrued interest). In the event of a default by the counterparty, realization of the collateral proceeds could be delayed, during which time the value of the collateral may decline.

Reverse Repurchase Agreements. To enhance its yield, the Fund may enter into reverse repurchase transactions under master repurchase agreements whereby the Fund sells securities to a counterparty in return for cash and agrees to repurchase those securities at a future date and agreed upon price. During the period that reverse repurchase transactions are outstanding, the Fund identifies the securities as pledged in its records with an initial value at least equal to its principal obligation under the agreement. The cash proceeds received by the Fund may be invested in other securities. To the extent cash proceeds received from the counterparty exceed the value of the securities sold, the counterparty may request additional collateral from the Fund. If the counterparty defaults on its obligation, because of insolvency or other reasons, the Fund could experience delays and costs in recovering the securities sold. Information regarding securities sold under a reverse repurchase agreement, if any, is included at the end of the Fund's Schedule of Investments and the cash proceeds are recorded as a liability in the accompanying Statement of Assets and Liabilities. The Fund continues to receive interest and dividend payments on the securities sold during the term of the reverse repurchase agreement. During the period, the average principal balance of reverse repurchase transactions was $144,096,658 and the weighted average interest rate was 1.73% with payments included in the Statement of Operations as a component of interest expense. At period end, there were no reverse repurchase agreements outstanding.

3. Fees and Other Transactions with Affiliates.

Management Fee and Expense Contract. Fidelity Management & Research Company LLC (the investment adviser) and its affiliates provide the Fund with investment management related services for which the Fund pays a monthly management fee that is based on an annual rate of .25% of the Fund's average net assets. Under the expense contract, total expenses of Fidelity Government Money Market Fund are limited to an annual rate of .42% of the class' average net assets, with certain exceptions.

Distribution and Service Plan Fees. In accordance with Rule 12b-1 of the 1940 Act, the Fund has adopted separate Distribution and Service Plans for each class of shares. Certain classes pay Fidelity Distributors Company LLC (FDC), an affiliate of the investment adviser, separate Distribution and Service Fees, each of which is based on an annual percentage of each class' average net assets. In addition, FDC may pay financial intermediaries for selling shares of the Fund and providing shareholder support services. For the period, the Distribution and Service Fee rates, total fees and amounts retained by FDC were as follows:

	Distribution Fee	Service Fee	Total Fees	Retained by FDC
Capital Reserves Class	.25%	.25%	$33,057,764	$2,588,389
Daily Money Class	-%	.25%	17,064,827	446,429
Advisor M Class	-%	.25%	168,779	501
			$50,291,370	$3,035,319

During the period, the investment adviser or its affiliates waived a portion of these fees.

Sales Load. FDC receives the proceeds of contingent deferred sales charges deferred sales charges for Daily Money Class shares purchased by exchange from Class A or Class M shares of a Fidelity fund that were subject to these charges. In addition, FDC receives deferred sales charges for Advisor M Class shares purchased by exchange from Class M shares of a Fidelity fund that were subject to these charges.

For the period, sales charge amounts retained by FDC were as follows:

	Retained by FDC
Daily Money Class	$3,218
Advisor M Class	$230

Transfer Agent Fees. Fidelity Investments Institutional Operations Company LLC (FIIOC), an affiliate of the investment adviser, is the transfer, dividend disbursing and shareholder servicing agent for each class of the Fund. FIIOC receives asset-based fees with respect to each account. FIIOC pays for typesetting, printing and mailing of shareholder reports, except proxy statements. Each class pays a transfer agent fee equal to an annual rate of .20% of class-level average net assets, with the exception of Premium Class and Class K6 which pays .10% and .01% of class-level average net assets, respectively.

Under the expense contract, Fidelity Government Money Market Fund will pay a portion of the transfer agent fee at an annual rate of up to .17% of class-level average net assets.

For the period, transfer agent fees for each class were as follows:

	Amount	% of Class-Level Average Net Assets
Capital Reserves Class	$13,223,106	.20
Daily Money Class	13,651,861	.20
Advisor M Class	135,023	.20
Fidelity Government Money Market Fund	195,751,561	.15
Premium Class	4,734,849	.10
Class K6	73,476	.01
	$227,569,876

During the period, the investment adviser or its affiliates waived a portion of these fees.

Other. During the period, the investment adviser reimbursed the Fund for certain losses in the amount of $17,680.

4. Expense Reductions.

The investment adviser contractually agreed to reimburse expenses of each class to the extent annual operating expenses exceeded certain levels of class-level average net assets as noted in the table below. This reimbursement will remain in place through August 31, 2021. Some expenses, for example the compensation of the independent Trustees and certain other expenses such as interest expense, are excluded from this reimbursement.

The following classes were in reimbursement during the period:

	Expense Limitations	Reimbursement
Capital Reserves Class	.95%	$997,268
Daily Money Class	.70%	1,017,824
Advisor M Class	.70%	11,787
Premium Class	.32%	2,132,071
Class K6	.25%	193,891
		$4,352,841

Additionally, the investment adviser or its affiliates voluntarily agreed to waive certain fees in order to avoid a negative yield. Such arrangements may be discontinued by the investment adviser at any time. For the period, the amount of the waiver for each class was as follows:

Capital Reserves Class	$4,415,204
Daily Money Class	2,364,574
Advisor M Class	36,623
Fidelity Government Money Market Fund	3,238,964

Through arrangements with the Fund's custodian and each class' transfer agent, credits realized as a result of certain uninvested cash balances were used to reduce the Fund's expenses. During the period, custodian credits reduced the Fund's expenses by $27,731. During the period, transfer agent credits reduced each class' expenses as noted in the table below.

	Expense reduction
Daily Money Class	13,173
Advisor M Class	8,016
Fidelity Government Money Market Fund	8,805
	$29,994

In addition, during the period, the investment adviser or an affiliate reimbursed the Fund $800 for an operational error which is included in the accompanying Statement of Operations.

5. Distributions to Shareholders.

Distributions to shareholders of each class were as follows:

	Year ended April 30, 2020	Year ended April 30, 2019
Distributions to shareholders
Capital Reserves Class	$60,356,967	$91,874,265
Daily Money Class	76,178,608	97,398,383
Advisor M Class	679,470	626,030
Fidelity Government Money Market Fund	1,678,425,378	1,713,973,458
Premium Class	68,936,329	66,197,174
Class K6	10,045,549	4,068,962
Total	$1,894,622,301	$1,974,138,272

6. Share Transactions.

Share transactions for each class of shares at a $1.00 per share were as follows and may contain automatic conversions between classes or exchanges between affiliated funds:

	Shares	Shares	Dollars	Dollars
	Year ended April 30, 2020	Year ended April 30, 2019	Year ended April 30, 2020	Year ended April 30, 2019
Capital Reserves Class
Shares sold	31,933,001,084	34,036,473,998	$31,933,001,084	$34,036,473,998
Reinvestment of distributions	37,539,053	56,430,056	37,539,053	56,430,056
Shares redeemed	(30,992,019,053)	(36,066,803,771)	(30,992,019,053)	(36,066,803,771)
Net increase (decrease)	978,521,084	(1,973,899,717)	$978,521,084	$(1,973,899,717)
Daily Money Class
Shares sold	28,776,861,260	24,000,323,722	$28,776,861,260	$24,000,323,722
Reinvestment of distributions	53,974,169	69,418,267	53,974,169	69,418,267
Shares redeemed	(27,034,456,625)	(24,944,431,256)	(27,034,456,625)	(24,944,431,257)
Net increase (decrease)	1,796,378,804	(874,689,267)	$1,796,378,804	$(874,689,268)
Advisor M Class
Shares sold	185,769,558	108,369,251	$185,769,558	$108,369,251
Reinvestment of distributions	655,877	599,065	655,877	599,065
Shares redeemed	(110,783,720)	(88,227,180)	(110,783,720)	(88,227,180)
Net increase (decrease)	75,641,715	20,741,136	$75,641,715	$20,741,136
Fidelity Government Money Market Fund
Shares sold	541,543,937,250	365,712,133,762	$541,543,937,250	$365,712,133,762
Reinvestment of distributions	1,535,792,307	1,557,490,330	1,535,792,307	1,557,490,330
Shares redeemed	(482,229,701,607)	(348,428,129,546)	(482,229,701,607)	(348,428,129,545)
Net increase (decrease)	60,850,027,950	18,841,494,546	$60,850,027,950	$18,841,494,547
Premium Class
Shares sold	5,782,487,798	3,529,451,047	$5,782,487,798	$3,529,451,047
Reinvestment of distributions	64,936,594	63,438,128	64,936,594	63,438,128
Shares redeemed	(4,237,106,538)	(2,379,405,678)	(4,237,106,538)	(2,379,405,678)
Net increase (decrease)	1,610,317,854	1,213,483,497	$1,610,317,854	$1,213,483,497
Class K6
Shares sold	1,582,341,872	473,757,227	$1,582,341,872	$473,757,227
Reinvestment of distributions	10,037,137	4,067,608	10,037,137	4,067,608
Shares redeemed	(683,867,826)	(119,589,388)	(683,867,826)	(119,589,388)
Net increase (decrease)	908,511,183	358,235,447	$908,511,183	$358,235,447

7. Other.

8. Coronavirus (COVID-19) Pandemic.

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of Fidelity Hereford Street Trust and Shareholders of Fidelity Government Money Market Fund

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Fidelity Government Money Market Fund (one of the funds constituting Fidelity Hereford Street Trust, referred to hereafter as the “Fund”) as of April 30, 2020, the related statement of operations for the year ended April 30, 2020, the statement of changes in net assets for each of the two years in the period ended April 30, 2020, including the related notes, and the financial highlights for each of the periods indicated therein (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Fund as of April 30, 2020, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended April 30, 2020 and the financial highlights for each of the periods indicated therein in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of April 30, 2020 by correspondence with the custodians and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

PricewaterhouseCoopers LLP

Boston, Massachusetts

June 11, 2020

We have served as the auditor of one or more investment companies in the Fidelity group of funds since 1932.

Trustees and Officers

The fund’s Statement of Additional Information (SAI) includes more information about the Trustees. To request a free copy, call Fidelity at 1-800-544-8544 if you’re an individual investing directly with Fidelity, call 1-800-835-5092 if you’re a plan sponsor or participant with Fidelity as your recordkeeper or call 1-877-208-0098 on institutional accounts or if you’re an advisor or invest through one.

Interested Trustees*:

Correspondence intended for a Trustee who is an interested person may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Abigail P. Johnson (1961)

Year of Election or Appointment: 2009

Trustee

Chairman of the Board of Trustees

Jennifer Toolin McAuliffe (1959)

Year of Election or Appointment: 2016

Trustee

* Determined to be an “Interested Trustee” by virtue of, among other things, his or her affiliation with the trust or various entities under common control with FMR.

Independent Trustees:

Correspondence intended for an Independent Trustee may be sent to Fidelity Investments, P.O. Box 55235, Boston, Massachusetts 02205-5235.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Elizabeth S. Acton (1951)

Year of Election or Appointment: 2013

Trustee

Ann E. Dunwoody (1953)

Year of Election or Appointment: 2018

Trustee

John Engler (1948)

Year of Election or Appointment: 2014

Trustee

Robert F. Gartland (1951)

Year of Election or Appointment: 2010

Trustee

Arthur E. Johnson (1947)

Year of Election or Appointment: 2008

Trustee

Chairman of the Independent Trustees

Michael E. Kenneally (1954)

Year of Election or Appointment: 2009

Trustee

Vice Chairman of the Independent Trustees

Marie L. Knowles (1946)

Year of Election or Appointment: 2001

Trustee

Mark A. Murray (1954)

Year of Election or Appointment: 2016

Trustee

Advisory Board Members and Officers:

Correspondence intended for an officer may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210. Officers appear below in alphabetical order.

Name, Year of Birth; Principal Occupation

Elizabeth Paige Baumann (1968)

Year of Election or Appointment: 2017

Anti-Money Laundering (AML) Officer

Craig S. Brown (1977)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Brown also serves as Assistant Treasurer of other funds. Mr. Brown is an employee of Fidelity Investments (2013-present).

John J. Burke III (1964)

Year of Election or Appointment: 2018

Chief Financial Officer

David J. Carter (1973)

Year of Election or Appointment: 2020

Assistant Secretary

Mr. Carter also serves as Assistant Secretary of other funds. Mr. Carter serves as Vice President, Associate General Counsel (2010-present) and is an employee of Fidelity Investments (2005-present).

Jonathan Davis (1968)

Year of Election or Appointment: 2010

Assistant Treasurer

Laura M. Del Prato (1964)

Year of Election or Appointment: 2018

President and Treasurer

Colm A. Hogan (1973)

Year of Election or Appointment: 2016

Assistant Treasurer

Cynthia Lo Bessette (1969)

Year of Election or Appointment: 2019

Secretary and Chief Legal Officer (CLO)

Chris Maher (1972)

Year of Election or Appointment: 2013

Assistant Treasurer

Nancy D. Prior (1967)

Year of Election or Appointment: 2014

Vice President

Kenneth B. Robins (1969)

Year of Election or Appointment: 2020

Chief Compliance Officer

Stacie M. Smith (1974)

Year of Election or Appointment: 2013

Assistant Treasurer

Marc L. Spector (1972)

Year of Election or Appointment: 2016

Deputy Treasurer

Jim Wegmann (1979)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Wegmann also serves as Assistant Treasurer of other funds. Mr. Wegmann is an employee of Fidelity Investments (2011-present).

Shareholder Expense Example

As a shareholder of the Fund, you incur two types of costs: (1) transaction costs and (2) ongoing costs, including management fees, distribution and/or service (12b-1) fees and other Fund expenses. This Example is intended to help you understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds.

The Example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period (November 1, 2019 to April 30, 2020).

Actual Expenses

Hypothetical Example for Comparison Purposes

	Annualized Expense Ratio-^A	Beginning Account Value November 1, 2019	Ending Account Value April 30, 2020	Expenses Paid During Period-^B November 1, 2019 to April 30, 2020
Capital Reserves Class	.82%
Actual		$1,000.00	$1,002.60	$4.08**
Hypothetical-^C		$1,000.00	$1,020.79	$4.12**
Daily Money Class	.64%
Actual		$1,000.00	$1,003.60	$3.19**
Hypothetical-^C		$1,000.00	$1,021.68	$3.22**
Advisor M Class	.61%
Actual		$1,000.00	$1,003.60	$3.04**
Hypothetical-^C		$1,000.00	$1,021.83	$3.07**
Fidelity Government Money Market Fund	.42%
Actual		$1,000.00	$1,004.70	$2.09
Hypothetical-^C		$1,000.00	$1,022.77	$2.11
Premium Class	.32%
Actual		$1,000.00	$1,005.20	$1.60
Hypothetical-^C		$1,000.00	$1,023.27	$1.61
Class K6	.25%
Actual		$1,000.00	$1,005.50	$1.25
Hypothetical-^C		$1,000.00	$1,023.62	$1.26

^A Annualized expense ratio reflects expenses net of applicable fee waivers.

^B Expenses are equal to each Class' annualized expense ratio, multiplied by the average account value over the period, multiplied by 182/366 (to reflect the one-half year period).

^C 5% return per year before expenses

** If certain fees were not voluntarily waived by the investment adviser or its affiliates during the period, the annualized expense ratio and the expenses paid in the actual and hypothetical examples above would have been as shown in table below:

	Annualized Expense Ratio-^(a)	Expenses Paid
Capital Reserves Class	.95%
Actual		$4.73
Hypothetical-^(b)		$4.77
Daily Money Class	.70%
Actual		$3.49
Hypothetical-^(b)		$3.52
Advisor M Class	.70%
Actual		$3.49
Hypothetical-^(b)		$3.52

(a) Annualized expense ratio reflects expenses net of applicable fee waivers.

(b) 5% return per year before expenses

Distributions (Unaudited)

A total of 47.90% of the dividends distributed during the fiscal year was derived from interest on U.S. Government securities which is generally exempt from state income tax.

The fund designates $317,812,096 of distributions paid during the period January 1, 2020 to April 30, 2020 as qualifying to be taxed as interest-related dividends for nonresident alien shareholders.

The fund will notify shareholders in January 2021 of amounts for use in preparing 2020 income tax returns.

Fidelity Investments

SPU-ANN-0620
1.703529.122

Fidelity Flex® Funds

Fidelity Flex® Government Money Market Fund

Annual Report

April 30, 2020

See the inside front cover for important information about access to your fund’s shareholder reports.

Fidelity Investments

Account Type	Website	Phone Number
Brokerage, Mutual Fund, or Annuity Contracts:	fidelity.com/mailpreferences	1-800-343-3548
Employer Provided Retirement Accounts:	netbenefits.fidelity.com/preferences (choose 'no' under Required Disclosures to continue to print)	1-800-343-0860
Advisor Sold Accounts Serviced Through Your Financial Intermediary:	Contact Your Financial Intermediary	Your Financial Intermediary's phone number
Advisor Sold Accounts Serviced by Fidelity:	institutional.fidelity.com	1-877-208-0098

Contents

Note to Shareholders
Investment Summary/Performance
Schedule of Investments
Financial Statements
Notes to Financial Statements
Report of Independent Registered Public Accounting Firm
Trustees and Officers
Shareholder Expense Example
Distributions

You may also call 1-800-544-3455 (for managed account clients) or 1-800-835-5092 (for retirement plan participants) to request a free copy of the proxy voting guidelines.

Standard & Poor's, S&P and S&P 500 are registered service marks of The McGraw-Hill Companies, Inc. and have been licensed for use by Fidelity Distributors Corporation.

Other third-party marks appearing herein are the property of their respective owners.

NOT FDIC INSURED •MAY LOSE VALUE •NO BANK GUARANTEE

Neither the Fund nor Fidelity Distributors Corporation is a bank.

Note to Shareholders:

Investment Summary/Performance (Unaudited)

Effective Maturity Diversification as of April 30, 2020

Days	% of fund's investments
1 - 7	62.7
8 - 30	13.1
31 - 60	14.3
61 - 90	3.6
91 - 180	6.1
> 180	0.2

Effective maturity is determined in accordance with the requirements of Rule 2a-7 under the Investment Company Act of 1940.

Asset Allocation (% of fund's net assets)

As of April 30, 2020
	U.S. Treasury Debt	19.2%
	U.S. Government Agency Debt	27.9%
	Repurchase Agreements	44.1%
	Net Other Assets (Liabilities)	8.8%

Current 7-Day Yields

	4/30/20
Fidelity Flex® Government Money Market Fund	0.28%

Schedule of Investments April 30, 2020

Showing Percentage of Net Assets

U.S. Treasury Debt - 19.2%
	Yield(a)	Principal Amount	Value
U.S. Treasury Obligations - 19.2%
U.S. Treasury Bills
5/5/20 to 10/6/20	0.08 to 1.59 %	$6,649,200	$6,645,859
U.S. Treasury Notes
5/31/20 to 1/31/22	0.28 to 1.62 (b)	3,150,000	3,153,704
TOTAL U.S. TREASURY DEBT
(Cost $9,799,563)			9,799,563

U.S. Government Agency Debt - 27.9%
Federal Agencies - 27.9%
Fannie Mae
6/5/20 to 7/6/21	0.05 to 0.29 (b)(c)	800,000	799,938
Federal Farm Credit Bank
8/21/20 to 12/30/20	0.25 to 0.98 (b)	600,000	599,763
Federal Home Loan Bank
5/1/20 to 5/13/21	0.03 to 1.64 (b)	12,625,000	12,623,322
Freddie Mac
9/8/20 to 2/5/21	0.04(b)(c)	200,000	199,946
TOTAL U.S. GOVERNMENT AGENCY DEBT
(Cost $14,222,969)			14,222,969

U.S. Government Agency Repurchase Agreement - 22.5%
	Maturity Amount	Value
In a joint trading account at 0.05% dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations) #	$1,499,002	$1,499,000
With:
BMO Harris Bank NA at 0.06%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $1,030,002, 1.17%, 1/20/49)	1,000,002	1,000,000
BNP Paribas, SA at 0.07%, dated 4/24/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $1,020,029, 0.00% - 3.00%, 5/15/20 - 4/20/50)	1,000,014	1,000,000
Citibank NA at 0.05%, dated 4/28/20 due 5/5/20 (Collateralized by U.S. Treasury Obligations valued at $1,020,012, 0.50% - 2.75%, 6/30/25 - 4/30/27)	1,000,010	1,000,000
Citigroup Global Capital Markets, Inc. at 0.05%, dated 4/28/20 due 5/5/20 (Collateralized by U.S. Government Obligations valued at $1,020,475, 3.50% - 6.00%, 9/1/48 - 10/1/48)	1,000,010	1,000,000
Deutsche Bank AG, New York at 0.06%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $989,832, 3.35%, 6/15/24)	961,002	961,000
Goldman Sachs & Co. at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $1,020,001, 3.00% - 6.00%, 12/1/26 - 4/1/50)	1,000,001	1,000,000
J.P. Morgan Securities, LLC at 0.05%, dated 4/28/20 due 5/5/20 (Collateralized by U.S. Government Obligations valued at $1,030,005, 3.00%, 2/15/47)	1,000,010	1,000,000
Morgan Stanley & Co., LLC at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $1,020,102, 1.83% - 7.00%, 2/1/24 - 4/1/47)	1,000,001	1,000,000
RBC Dominion Securities at 0.06%, dated 4/21/20 due 5/5/20 (Collateralized by U.S. Treasury Obligations valued at $1,020,117, 0.88% - 4.50%, 7/31/26 - 7/1/49)	1,000,023	1,000,000
RBC Financial Group at 0.06%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Government Obligations valued at $1,027,373, 2.50% - 4.00%, 4/25/42 - 8/1/49)	1,000,002	1,000,000
TOTAL U.S. GOVERNMENT AGENCY REPURCHASE AGREEMENT
(Cost $11,460,000)		11,460,000

U.S. Treasury Repurchase Agreement - 21.6%
With:
BMO Harris Bank NA at 1.6%, dated 2/10/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $104,024, 2.63% - 2.88%, 03/31/25 - 10/15/21)	100,404	100,000
BNP Paribas, SA at 1.61%, dated 2/18/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $205,923, 0.17% - 4.63%, 7/31/20 - 11/15/49)	200,805	200,000
Commerz Markets LLC at 0.05%, dated 4/28/20 due 5/5/20 (Collateralized by U.S. Treasury Obligations valued at $1,020,016, 2.63%, 6/30/23)	1,000,010	1,000,000
Credit AG at:
0.09%, dated 4/23/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $1,030,123, 3.38%, 11/15/48)	1,000,083	1,000,000
0.13%, dated 4/20/20 due 5/7/20 (Collateralized by U.S. Treasury Obligations valued at $1,030,123, 3.38%, 11/15/48)	1,000,108	1,000,000
Credit Agricole CIB at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $1,019,128, 2.38%, 8/15/24)	1,000,001	1,000,000
Fixed Income Clearing Corp. - BNYM at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $1,020,048, 2.75%, 6/30/25)	1,000,001	1,000,000
HSBC Securities, Inc. at 0.04%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $1,029,966, 2.00%, 11/15/26)	1,000,001	1,000,000
Mizuho Bank, Ltd. at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $1,168,709, 2.38%, 5/15/29)	1,000,001	1,000,000
Mizuho Securities U.S.A., Inc. at 0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $1,020,543, 3.00%, 9/30/25)	1,000,001	1,000,000
MUFG Securities EMEA PLC at:
0.05%, dated 4/30/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $1,020,038, 1.13%, 2/28/25)	1,000,001	1,000,000
0.07%, dated:
4/24/20 due 5/1/20 (Collateralized by U.S. Treasury Obligations valued at $108,745, 2.25% - 3.13%, 11/15/27 - 8/15/44)	100,001	100,000
4/30/20 due:
5/4/20 (Collateralized by U.S. Treasury Obligations valued at $108,870, 1.63% - 3.00%, 6/30/25 - 2/15/47)	100,001	100,000
5/7/20 (Collateralized by U.S. Treasury Obligations valued at $108,895, 2.63% - 3.00%, 2/15/29 - 2/15/47)	100,001	100,000
0.08%, dated:
4/27/20 due 5/4/20 (Collateralized by U.S. Treasury Obligations valued at $210,941, 2.88% - 3.13%, 11/30/23 - 8/15/44)	200,003	200,000
4/30/20 due 5/7/20
(Collateralized by U.S. Treasury Obligations valued at $108,988, 2.75% - 3.00%, 11/15/23 - 2/15/47)	100,003	100,000
(Collateralized by U.S. Treasury Obligations valued at $109,003, 1.13% - 3.00%, 2/28/22 - 2/15/47)	100,003	100,000
RBC Dominion Securities at 0.05%, dated 4/21/20 due 5/5/20 (Collateralized by U.S. Treasury Obligations valued at $1,020,039, 0.50% - 3.75%, 3/31/25 - 8/15/49)	1,000,019	1,000,000
TOTAL U.S. TREASURY REPURCHASE AGREEMENT
(Cost $11,000,000)		11,000,000
TOTAL INVESTMENT IN SECURITIES - 91.2%
(Cost $46,482,532)		46,482,532
NET OTHER ASSETS (LIABILITIES) - 8.8%		4,459,606
NET ASSETS - 100%		$50,942,138

Legend

(a) Yield represents either the annualized yield at the date of purchase, or the stated coupon rate, or, for floating and adjustable rate securities, the rate at period end.

(b) Coupon rates for floating and adjustable rate securities reflect the rates in effect at period end.

(c) Coupon is indexed to a floating interest rate which may be multiplied by a specified factor and/or subject to caps or floors.

Investment Valuation

Other Information

# Additional information on each counterparty to the repurchase agreement is as follows:

Repurchase Agreement / Counterparty	Value
$1,499,000 due 5/01/20 at 0.05%
BNP Paribas, S.A.	$25,000
Bank Of America, N.A.	238,000
Citibank NA	66,000
Citigroup Global Markets, Inc.	38,000
Credit Agricole CIB New York Branch	139,000
ING Financial Markets LLC	20,000
J.P. Morgan Securities LLC	580,000
Mitsubishi UFJ Securities Holdings Ltd.	168,000
Mitsubishi UFJ Securities (USA)	17,000
Mizuho Securities USA, Inc.	119,000
Wells Fargo Securities LLC	89,000
	$1,499,000

See accompanying notes which are an integral part of the financial statements.

Financial Statements

Statement of Assets and Liabilities

		April 30, 2020
Assets
Investment in securities, at value (including repurchase agreements of $22,460,000) — See accompanying schedule: Unaffiliated issuers (cost $46,482,532)		$46,482,532
Cash		155
Receivable for fund shares sold		5,892,570
Interest receivable		26,660
Total assets		52,401,917
Liabilities
Payable for investments purchased	$199,880
Payable for fund shares redeemed	1,255,911
Distributions payable	3,988
Total liabilities		1,459,779
Net Assets		$50,942,138
Net Assets consist of:
Paid in capital		$50,942,149
Total accumulated earnings (loss)		(11)
Net Assets		$50,942,138
Net Asset Value, offering price and redemption price per share ($50,942,138 ÷ 50,941,071 shares)		$1.00

See accompanying notes which are an integral part of the financial statements.

Statement of Operations

		Year ended April 30, 2020
Investment Income
Interest		$609,348
Expenses
Independent trustees' fees and expenses	$126
Interest	8
Total expenses before reductions	134
Expense reductions	(11)
Total expenses after reductions		123
Net investment income (loss)		609,225
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment securities:
Unaffiliated issuers		1,084
Total net realized gain (loss)		1,084
Net increase in net assets resulting from operations		$610,309

See accompanying notes which are an integral part of the financial statements.

Statement of Changes in Net Assets

	Year ended April 30, 2020	Year ended April 30, 2019
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$609,225	$511,814
Net realized gain (loss)	1,084	35
Net increase in net assets resulting from operations	610,309	511,849
Distributions to shareholders	(609,282)	(511,814)
Share transactions
Proceeds from sales of shares	1,066,466,133	18,861,061
Reinvestment of distributions	481,328	447,039
Cost of shares redeemed	(1,038,050,400)	(50,948,612)
Net increase (decrease) in net assets and shares resulting from share transactions	28,897,061	(31,640,512)
Total increase (decrease) in net assets	28,898,088	(31,640,477)
Net Assets
Beginning of period	22,044,050	53,684,527
End of period	$50,942,138	$22,044,050
Other Information
Shares
Sold	1,066,466,133	18,861,061
Issued in reinvestment of distributions	481,328	447,039
Redeemed	(1,038,050,400)	(50,948,612)
Net increase (decrease)	28,897,061	(31,640,512)

See accompanying notes which are an integral part of the financial statements.

Financial Highlights

Fidelity Flex Government Money Market Fund


Years ended April 30,	2020	2019	2018	2017 ^A
Selected Per–Share Data
Net asset value, beginning of period	$1.00	$1.00	$1.00	$1.00
Income from Investment Operations
Net investment income (loss)	.018	.022	.012	.001
Net realized and unrealized gain (loss)	–^B	–^B	–^B	–
Total from investment operations	.018	.022	.012	.001
Distributions from net investment income	(.018)	(.022)	(.012)	(.001)
Total distributions	(.018)	(.022)	(.012)	(.001)
Net asset value, end of period	$1.00	$1.00	$1.00	$1.00
Total Return^C,^D	1.81%	2.22%	1.23%	.12%
Ratios to Average Net Assets^E
Expenses before reductions^F	-%	-%	-%	- %^G
Expenses net of fee waivers, if any^F	-%	-%	-%	- %^G
Expenses net of all reductions^F	-%	-%	-%	- %^G
Net investment income (loss)	1.64%	2.14%	1.39%	.78%^G
Supplemental Data
Net assets, end of period (000 omitted)	$50,942	$22,044	$53,685	$5,006

^A For the period March 8, 2017 (commencement of operations) to April 30, 2017.

^B Amount represents less than $.0005 per share.

^C Total returns for periods of less than one year are not annualized.

^D Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^E Expense ratios reflect operating expenses of the Fund. Expenses before reductions do not reflect amounts reimbursed or waived or reductions from expense offset arrangements and do not represent the amount paid by the Fund during periods when reimbursements, waivers or reductions occur. Expenses net of fee waivers reflect expenses after reimbursement and waivers but prior to reductions from expense offset arrangements. Expenses net of all reductions represent the net expenses paid by the Fund.

^F Amount represents less than .005%.

^G Annualized

See accompanying notes which are an integral part of the financial statements.

Notes to Financial Statements

For the period ended April 30, 2020

1. Organization.

Fidelity Flex Government Money Market Fund (the Fund) is a fund of Fidelity Hereford Street Trust (the Trust) and is authorized to issue an unlimited number of shares. Share transactions on the Statement of Changes in Net Assets may contain exchanges between affiliated funds. The Trust is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company organized as a Delaware statutory trust. The Fund is available only to certain fee-based accounts offered by Fidelity.

Effective January 1, 2020:

2. Significant Accounting Policies.

Investment Valuation. The Fund categorizes the inputs to valuation techniques used to value its investments into a disclosure hierarchy consisting of three levels as shown below:

Level 1 – quoted prices in active markets for identical investments
Level 2 – other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, etc.)
Level 3 – unobservable inputs (including the Fund's own assumptions based on the best information available)

Investment Transactions and Income. The net asset value per share for processing shareholder transactions is calculated as of the close of business of the New York Stock Exchange (NYSE), normally 4:00 p.m. Eastern time. Security transactions are accounted for as of trade date. Gains and losses on securities sold are determined on the basis of identified cost. Interest income is accrued as earned and includes coupon interest and amortization of premium and accretion of discount on debt securities as applicable.

As of period end, the cost and unrealized appreciation (depreciation) in securities for federal income tax purposes were as follows:

Gross unrealized appreciation	$–
Gross unrealized depreciation	–
Net unrealized appreciation (depreciation)	$–
Tax Cost	$46,482,532

The tax character of distributions paid was as follows:

	April 30, 2020	April 30, 2019
Ordinary Income	$609,282	$ 511,814

Repurchase Agreements. Pursuant to an Exemptive Order issued by the Securities and Exchange Commission (the SEC), the Fund along with other registered investment companies having management contracts with Fidelity Management & Research Company LLC (FMR), or other affiliated entities of FMR, are permitted to transfer uninvested cash balances into joint trading accounts which are then invested in repurchase agreements. The Fund may also invest directly with institutions in repurchase agreements. Repurchase agreements may be collateralized by cash or government securities. Upon settlement date, collateral is held in segregated accounts with custodian banks and may be obtained in the event of a default of the counterparty. The Fund monitors, on a daily basis, the value of the collateral to ensure it is at least equal to the principal amount of the repurchase agreement (including accrued interest). In the event of a default by the counterparty, realization of the collateral proceeds could be delayed, during which time the value of the collateral may decline.

Reverse Repurchase Agreements. To enhance its yield, the Fund may enter into reverse repurchase transactions under master repurchase agreements whereby the Fund sells securities to a counterparty in return for cash and agrees to repurchase those securities at a future date and agreed upon price. During the period that reverse repurchase transactions are outstanding, the Fund identifies the securities as pledged in its records with an initial value at least equal to its principal obligation under the agreement. The cash proceeds received by the Fund may be invested in other securities. To the extent cash proceeds received from the counterparty exceed the value of the securities sold, the counterparty may request additional collateral from the Fund. If the counterparty defaults on its obligation, because of insolvency or other reasons, the Fund could experience delays and costs in recovering the securities sold. Information regarding securities sold under a reverse repurchase agreement, if any, is included at the end of the Fund's Schedule of Investments and the cash proceeds are recorded as a liability in the accompanying Statement of Assets and Liabilities. The Fund continues to receive interest and dividend payments on the securities sold during the term of the reverse repurchase agreement. During the period, the average principal balance of reverse repurchase transactions was $99,990 and the weighted average interest rate was 1.43% with payments included in the Statement of Operations as a component of interest expense. At period end, there were no reverse repurchase agreements outstanding.

3. Fees and Other Transactions with Affiliates.

Management Fee. Fidelity Management & Research Company LLC (the investment adviser) and its affiliates provide the Fund with investment management related services and the Fund does not pay any fees for these services. Under the management contract, the investment adviser or an affiliate pays all other expenses of the Fund, excluding fees and expenses of the independent Trustees, and certain miscellaneous expenses such as proxy and shareholder meeting expenses.

4. Expense Reductions.

Through arrangements with the Fund's custodian, credits realized as a result of certain uninvested cash balances were used to reduce the Fund's expenses by $11.

5. Other.

6. Coronavirus (COVID-19) Pandemic.

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of Fidelity Hereford Street Trust and Shareholders of Fidelity Flex Government Money Market Fund

Opinion on the Financial Statements

We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Fidelity Flex Government Money Market Fund (one of the funds constituting Fidelity Hereford Street Trust, referred to hereafter as the “Fund”) as of April 30, 2020, the related statement of operations for the year ended April 30, 2020, the statement of changes in net assets for each of the two years in the period ended April 30, 2020, including the related notes, and the financial highlights for each of the three years in the period ended April 30, 2020 and for the period March 8, 2017 (commencement of operations) through April 30, 2017 (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Fund as of April 30, 2020, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period ended April 30, 2020 and the financial highlights for each of the three years in the period ended April 30, 2020 and for the period March 8, 2017 (commencement of operations) through April 30, 2017 in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our procedures included confirmation of securities owned as of April 30, 2020 by correspondence with the custodians and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

PricewaterhouseCoopers LLP

Boston, Massachusetts

June 10, 2020

We have served as the auditor of one or more investment companies in the Fidelity group of funds since 1932.

Trustees and Officers

The fund’s Statement of Additional Information (SAI) includes more information about the Trustees. To request a free copy, call Fidelity at 1-800-544-3455 (for managed account clients) or 1-800-835-5092 (for retirement plan participants).

Interested Trustees*:

Correspondence intended for a Trustee who is an interested person may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Abigail P. Johnson (1961)

Year of Election or Appointment: 2009

Trustee

Chairman of the Board of Trustees

Jennifer Toolin McAuliffe (1959)

Year of Election or Appointment: 2016

Trustee

* Determined to be an “Interested Trustee” by virtue of, among other things, his or her affiliation with the trust or various entities under common control with FMR.

Independent Trustees:

Correspondence intended for an Independent Trustee may be sent to Fidelity Investments, P.O. Box 55235, Boston, Massachusetts 02205-5235.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Elizabeth S. Acton (1951)

Year of Election or Appointment: 2013

Trustee

Ann E. Dunwoody (1953)

Year of Election or Appointment: 2018

Trustee

John Engler (1948)

Year of Election or Appointment: 2014

Trustee

Robert F. Gartland (1951)

Year of Election or Appointment: 2010

Trustee

Arthur E. Johnson (1947)

Year of Election or Appointment: 2008

Trustee

Chairman of the Independent Trustees

Michael E. Kenneally (1954)

Year of Election or Appointment: 2009

Trustee

Vice Chairman of the Independent Trustees

Marie L. Knowles (1946)

Year of Election or Appointment: 2001

Trustee

Mark A. Murray (1954)

Year of Election or Appointment: 2016

Trustee

Advisory Board Members and Officers:

Correspondence intended for an officer may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210. Officers appear below in alphabetical order.

Name, Year of Birth; Principal Occupation

Elizabeth Paige Baumann (1968)

Year of Election or Appointment: 2017

Anti-Money Laundering (AML) Officer

Craig S. Brown (1977)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Brown also serves as Assistant Treasurer of other funds. Mr. Brown is an employee of Fidelity Investments (2013-present).

John J. Burke III (1964)

Year of Election or Appointment: 2018

Chief Financial Officer

David J. Carter (1973)

Year of Election or Appointment: 2020

Assistant Secretary

Mr. Carter also serves as Assistant Secretary of other funds. Mr. Carter serves as Vice President, Associate General Counsel (2010-present) and is an employee of Fidelity Investments (2005-present).

Jonathan Davis (1968)

Year of Election or Appointment: 2010

Assistant Treasurer

Laura M. Del Prato (1964)

Year of Election or Appointment: 2018

President and Treasurer

Colm A. Hogan (1973)

Year of Election or Appointment: 2016

Assistant Treasurer

Cynthia Lo Bessette (1969)

Year of Election or Appointment: 2019

Secretary and Chief Legal Officer (CLO)

Chris Maher (1972)

Year of Election or Appointment: 2013

Assistant Treasurer

Nancy D. Prior (1967)

Year of Election or Appointment: 2014

Vice President

Kenneth B. Robins (1969)

Year of Election or Appointment: 2020

Chief Compliance Officer

Stacie M. Smith (1974)

Year of Election or Appointment: 2013

Assistant Treasurer

Marc L. Spector (1972)

Year of Election or Appointment: 2016

Deputy Treasurer

Jim Wegmann (1979)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Wegmann also serves as Assistant Treasurer of other funds. Mr. Wegmann is an employee of Fidelity Investments (2011-present).

Shareholder Expense Example

As a shareholder of the Fund, you incur two types of costs: (1) transaction costs and (2) ongoing costs, including other Fund expenses. This Example is intended to help you understand your ongoing costs (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds.

The Example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period (November 1, 2019 to April 30, 2020).

Actual Expenses

Hypothetical Example for Comparison Purposes

	Annualized Expense Ratio-^A	Beginning Account Value November 1, 2019	Ending Account Value April 30, 2020	Expenses Paid During Period-^B November 1, 2019 to April 30, 2020
Actual	- %-^C	$1,000.00	$1,006.50	$--^D
Hypothetical-^E		$1,000.00	$1,024.86	$--^D

^A Annualized expense ratio reflects expenses net of applicable fee waivers.

^B Expenses are equal to the Fund's annualized expense ratio, multiplied by the average account value over the period, multiplied by 182/366 (to reflect the one-half year period).

^C Amount represents less than .005%.

^D Amount represents less than $.005.

^E 5% return per year before expenses

Distributions (Unaudited)

A total of 19.48% of the dividends distributed during the fiscal year was derived from interest on U.S. Government securities which is generally exempt from state income tax.

The fund designates $145,347 of distributions paid during the period January 1, 2020 to April 30, 2020 as qualifying to be taxed as interest-related dividends for nonresident alien shareholders.

The fund will notify shareholders in January 2021 of amounts for use in preparing 2020 income tax returns.

Fidelity Investments

ZGY-ANN-0620
1.9881599.103

Fidelity® Series Treasury Bill Index Fund

Annual Report

April 30, 2020

See the inside front cover for important information about access to your fund’s shareholder reports.

Fidelity Investments

Account Type	Website	Phone Number
Brokerage, Mutual Fund, or Annuity Contracts:	fidelity.com/mailpreferences	1-800-343-3548
Employer Provided Retirement Accounts:	netbenefits.fidelity.com/preferences (choose 'no' under Required Disclosures to continue to print)	1-800-343-0860
Advisor Sold Accounts Serviced Through Your Financial Intermediary:	Contact Your Financial Intermediary	Your Financial Intermediary's phone number
Advisor Sold Accounts Serviced by Fidelity:	institutional.fidelity.com	1-877-208-0098

Contents

Note to Shareholders
Performance
Management's Discussion of Fund Performance
Investment Summary
Schedule of Investments
Financial Statements
Notes to Financial Statements
Report of Independent Registered Public Accounting Firm
Trustees and Officers
Shareholder Expense Example
Distributions
Liquidity Risk Management Program

You may also call 1-800-544-8544 to request a free copy of the proxy voting guidelines.

Standard & Poor's, S&P and S&P 500 are registered service marks of The McGraw-Hill Companies, Inc. and have been licensed for use by Fidelity Distributors Corporation.

Other third-party marks appearing herein are the property of their respective owners.

NOT FDIC INSURED •MAY LOSE VALUE •NO BANK GUARANTEE

Neither the Fund nor Fidelity Distributors Corporation is a bank.

Note to Shareholders:

Performance: The Bottom Line

Average annual total return reflects the change in the value of an investment, assuming reinvestment of distributions from dividend income and capital gains (the profits earned upon the sale of securities that have grown in value, if any) and assuming a constant rate of performance each year. The hypothetical investment and the average annual total returns do not reflect the deduction of taxes that a shareholder would pay on fund distributions or the redemption of fund shares. During periods of reimbursement by Fidelity, a fund’s total return will be greater than it would be had the reimbursement not occurred. How a fund did yesterday is no guarantee of how it will do tomorrow.

Average Annual Total Returns

For the periods ended April 30, 2020	Past 1 year	Life of fund^A
Fidelity® Series Treasury Bill Index Fund	2.34%	2.33%

^A From August 17, 2018

$10,000 Over Life of Fund

The chart shows how the value of your investment would have changed, and also shows how the Bloomberg Barclays U.S. 3-6 Month Treasury Bill Index performed over the same period.

	Period Ending Values
	$10,400	Fidelity® Series Treasury Bill Index Fund
	$10,407	Bloomberg Barclays U.S. 3-6 Month Treasury Bill Index

Management's Discussion of Fund Performance

Market Recap: U.S. taxable investment-grade bonds rose strongly for the 12 months ending April 30, 2020, a period dominated by global economic uncertainty, growing risk aversion and falling U.S. Treasury yields. The Bloomberg Barclays U.S. Aggregate Bond Index gained 10.84% for the period. Treasury market yields began their descent beginning in August, shortly after the Federal Reserve reduced policy interest rates for the first time since 2008, citing signs of weakness in some segments of the U.S. economy. The Fed followed with rate cuts of 25 basis points each in September and October. Yields fell from January through mid-March, due to robust investor demand for most fixed-income assets – especially U.S. Treasury bonds – as the outbreak and spread of the new coronavirus hampered global economic growth and corporate earnings. The Fed announced two emergency rate cuts in March, which reduced the fed funds rate to a range of 0% to 0.25%, the low last seen at the height of the financial crisis of 2008. Market yields stabilized a bit in April. Within the Bloomberg Barclays Aggregate index, U.S. Treasury bonds gained 14.27%. Corporate bonds, in comparison, gained 9.88%. Outside the index, U.S. corporate high-yield bonds returned -4.11%, while Treasury Inflation-Protected Securities (TIPS) rose 7.95%.

Comments from Co-Portfolio Managers Brandon Bettencourt and Jay Small: For the fiscal year, the fund gained 2.34%, roughly in line with the 2.37% advance of the Bloomberg Barclays 3-6 Month Treasury Bill Index. These results met our goal of producing monthly returns, before expenses, that closely match the benchmarks’ returns. We use a method known as stratified sampling, which matches the index’s risk factors, but does not always hold all bonds in the exact proportions of the index. For the fiscal year, Treasury securities of all maturities posted some of their best-ever returns, bolstered initially by the U.S. Federal Reserve’s early-2019 pivot toward a more dovish interest-rate stance and later by three interest-rate cuts in the second half of 2019. Even though the Fed held rates steady from November 2019 through the end of February 2020, Treasury yields continued to slide and their prices rose amid growing expectations for additional U.S. rate cuts. Those expectations were met in in March when the U.S. central bank cut rates to combat the economic consequences of the global coronavirus pandemic. For the year, long-maturity Treasuries, with their greater sensitivity to interest-rate movements, generated near-historic gains and outpaced the still unusually large advances of intermediate- and short-term Treasuries.

The views expressed above reflect those of the portfolio manager(s) only through the end of the period as stated on the cover of this report and do not necessarily represent the views of Fidelity or any other person in the Fidelity organization. Any such views are subject to change at any time based upon market or other conditions and Fidelity disclaims any responsibility to update such views. These views may not be relied on as investment advice and, because investment decisions for a Fidelity fund are based on numerous factors, may not be relied on as an indication of trading intent on behalf of any Fidelity fund.

Investment Summary (Unaudited)

Asset Allocation (% of fund's net assets)

As of April 30, 2020
	U.S. Government and U.S. Government Agency Obligations	100.0%

Schedule of Investments April 30, 2020

Showing Percentage of Net Assets

U.S. Government and Government Agency Obligations - 100.0%
	Principal Amount	Value
U.S. Treasury Obligations - 100.0%
U.S. Treasury Bills, yield at date of purchase 0.03% to 1.09% 8/6/20 to 10/29/20
(Cost $2,209,772,299)	$2,212,490,000	$2,211,505,730
TOTAL U.S. GOVERNMENT AND GOVERNMENT AGENCY OBLIGATIONS
(Cost $2,209,772,299)		2,211,505,730
	Shares	Value

Money Market Funds - 0.2%
Fidelity Cash Central Fund 0.16% (a)
(Cost $4,423,161)	4,421,954	4,423,280
TOTAL INVESTMENT IN SECURITIES - 100.2%
(Cost $2,214,195,460)		2,215,929,010
NET OTHER ASSETS (LIABILITIES) - (0.2)%		(4,027,938)
NET ASSETS - 100%		$2,211,901,072

Legend

(a) Affiliated fund that is generally available only to investment companies and other accounts managed by Fidelity Investments. The rate quoted is the annualized seven-day yield of the fund at period end. A complete unaudited listing of the fund's holdings as of its most recent quarter end is available upon request. In addition, each Fidelity Central Fund's financial statements, which are not covered by the Fund's Report of Independent Registered Public Accounting Firm, are available on the SEC's website or upon request.

Affiliated Central Funds

Information regarding fiscal year to date income earned by the Fund from investments in Fidelity Central Funds is as follows:

Fund	Income earned
Fidelity Cash Central Fund	$75,201
Total	$75,201

Amounts in the income column in the above table include any capital gain distributions from underlying funds, which are presented in the corresponding line-item in the Statement of Operations, if applicable.

Investment Valuation

The following is a summary of the inputs used, as of April 30, 2020, involving the Fund's assets and liabilities carried at fair value. The inputs or methodology used for valuing securities may not be an indication of the risk associated with investing in those securities. For more information on valuation inputs, and their aggregation into the levels used below, please refer to the Investment Valuation section in the accompanying Notes to Financial Statements.

	Valuation Inputs at Reporting Date:
Description	Total	Level 1	Level 2	Level 3
Investments in Securities:
U.S. Government and Government Agency Obligations	$2,211,505,730	$--	$2,211,505,730	$--
Money Market Funds	4,423,280	4,423,280	--	--
Total Investments in Securities:	$2,215,929,010	$4,423,280	$2,211,505,730	$--

See accompanying notes which are an integral part of the financial statements.

Financial Statements

Statement of Assets and Liabilities

		April 30, 2020
Assets
Investment in securities, at value — See accompanying schedule: Unaffiliated issuers (cost $2,209,772,299)	$2,211,505,730
Fidelity Central Funds (cost $4,423,161)	4,423,280
Total Investment in Securities (cost $2,214,195,460)		$2,215,929,010
Receivable for investments sold		897,092,796
Receivable for fund shares sold		101,623,110
Distributions receivable from Fidelity Central Funds		249
Total assets		3,214,645,165
Liabilities
Payable for investments purchased	$1,002,606,977
Payable for fund shares redeemed	129,830
Other payables and accrued expenses	7,286
Total liabilities		1,002,744,093
Net Assets		$2,211,901,072
Net Assets consist of:
Paid in capital		$2,204,642,649
Total accumulated earnings (loss)		7,258,423
Net Assets		$2,211,901,072
Net Asset Value, offering price and redemption price per share ($2,211,901,072 ÷ 220,464,555 shares)		$10.03

See accompanying notes which are an integral part of the financial statements.

Statement of Operations

		Year ended April 30, 2020
Investment Income
Interest		$26,909,128
Income from Fidelity Central Funds		75,201
Total income		26,984,329
Expenses
Custodian fees and expenses	$16,725
Independent trustees' fees and expenses	5,263
Commitment fees	3,662
Total expenses before reductions	25,650
Expense reductions	(38)
Total expenses after reductions		25,612
Net investment income (loss)		26,958,717
Realized and Unrealized Gain (Loss)
Net realized gain (loss) on:
Investment securities:
Unaffiliated issuers	7,173,562
Fidelity Central Funds	217
Total net realized gain (loss)		7,173,779
Change in net unrealized appreciation (depreciation) on:
Investment securities:
Unaffiliated issuers	1,718,867
Fidelity Central Funds	115
Total change in net unrealized appreciation (depreciation)		1,718,982
Net gain (loss)		8,892,761
Net increase (decrease) in net assets resulting from operations		$35,851,478

See accompanying notes which are an integral part of the financial statements.

Statement of Changes in Net Assets

	Year ended April 30, 2020	For the period August 17, 2018 (commencement of operations) to April 30, 2019
Increase (Decrease) in Net Assets
Operations
Net investment income (loss)	$26,958,717	$12,413,490
Net realized gain (loss)	7,173,779	(77,759)
Change in net unrealized appreciation (depreciation)	1,718,982	14,568
Net increase (decrease) in net assets resulting from operations	35,851,478	12,350,299
Distributions to shareholders	(27,218,002)	(13,725,351)
Share transactions
Proceeds from sales of shares	1,706,513,777	983,129,096
Reinvestment of distributions	26,852,126	13,725,351
Cost of shares redeemed	(457,528,974)	(68,048,728)
Net increase (decrease) in net assets resulting from share transactions	1,275,836,929	928,805,719
Total increase (decrease) in net assets	1,284,470,405	927,430,667
Net Assets
Beginning of period	927,430,667	–
End of period	$2,211,901,072	$927,430,667
Other Information
Shares
Sold	170,579,768	98,330,645
Issued in reinvestment of distributions	2,683,799	1,373,521
Redeemed	(45,695,532)	(6,807,646)
Net increase (decrease)	127,568,035	92,896,520

See accompanying notes which are an integral part of the financial statements.

Financial Highlights

Fidelity Series Treasury Bill Index Fund


Years ended April 30,	2020	2019 ^A
Selected Per–Share Data
Net asset value, beginning of period	$9.98	$10.00
Income from Investment Operations
Net investment income (loss)^B	.169	.166
Net realized and unrealized gain (loss)	.062	(.005)
Total from investment operations	.231	.161
Distributions from net investment income	(.175)	(.181)
Distributions from net realized gain	(.006)	–
Total distributions	(.181)	(.181)
Net asset value, end of period	$10.03	$9.98
Total Return^C,^D	2.34%	1.62%
Ratios to Average Net Assets^E,^F
Expenses before reductions^G	-%	- %^H
Expenses net of fee waivers, if any^G	-%	- %^H
Expenses net of all reductions^G	-%	- %^H
Net investment income (loss)	1.69%	2.36%^H
Supplemental Data
Net assets, end of period (000 omitted)	$2,211,901	$927,431

^A For the period August 17, 2018 (commencement of operations) to April 30, 2019.

^B Calculated based on average shares outstanding during the period.

^C Total returns for periods of less than one year are not annualized.

^D Total returns would have been lower if certain expenses had not been reduced during the applicable periods shown.

^E Fees and expenses of any underlying Fidelity Central Funds are not included in the Fund's expense ratio. The Fund indirectly bears its proportionate share of the expenses of any underlying Fidelity Central Funds.

^F Expense ratios reflect operating expenses of the Fund. Expenses before reductions do not reflect amounts reimbursed by the investment adviser or reductions from expense offset arrangements and do not represent the amount paid by the Fund during periods when reimbursements or reductions occur. Expense ratios before reductions for start-up periods may not be representative of longer term operating periods. Expenses net of fee waivers reflect expenses after reimbursement by the investment adviser but prior to reductions from expense offset arrangements. Expenses net of all reductions represent the net expenses paid by the Fund.

^G Amount represents less than .005%.

^H Annualized

See accompanying notes which are an integral part of the financial statements.

Notes to Financial Statements

For the period ended April 30, 2020

1. Organization.

Fidelity Series Treasury Bill Index Fund (the Fund) is a fund of Fidelity Hereford Street Trust (the Trust) and is authorized to issue an unlimited number of shares. Shares are offered only to certain other Fidelity funds and Fidelity managed 529 plans. The Trust is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company organized as a Delaware statutory trust.

Effective January 1, 2020:

2. Investments in Fidelity Central Funds.

The Fund invests in Fidelity Central Funds, which are open-end investment companies generally available only to other investment companies and accounts managed by the investment adviser and its affiliates. The Fund's Schedule of Investments lists each of the Fidelity Central Funds held as of period end, if any, as an investment of the Fund, but does not include the underlying holdings of each Fidelity Central Fund. As an Investing Fund, the Fund indirectly bears its proportionate share of the expenses of the underlying Fidelity Central Funds.

The Money Market Central Funds seek preservation of capital and current income and are managed by the investment adviser. Annualized expenses of the Money Market Central Funds as of their most recent shareholder report date ranged from less than .005% to .01%.

A complete unaudited list of holdings for each Fidelity Central Fund is available upon request or at the Securities and Exchange Commission (the SEC) website at www.sec.gov. In addition, the financial statements of the Fidelity Central Funds, which are not covered by the Fund's Report of Independent Registered Public Accounting Firm, are available on the SEC website or upon request.

3. Significant Accounting Policies.

Investment Valuation. Investments are valued as of 4:00 p.m. Eastern time on the last calendar day of the period. The Board of Trustees (the Board) has delegated the day to day responsibility for the valuation of the Fund's investments to the Fair Value Committee (the Committee) established by the Fund's investment adviser. In accordance with valuation policies and procedures approved by the Board, the Fund attempts to obtain prices from one or more third party pricing vendors or brokers to value its investments. When current market prices, quotations or currency exchange rates are not readily available or reliable, investments will be fair valued in good faith by the Committee, in accordance with procedures adopted by the Board. Factors used in determining fair value vary by investment type and may include market or investment specific events, changes in interest rates and credit quality. The frequency with which these procedures are used cannot be predicted and they may be utilized to a significant extent. The Committee oversees the Fund's valuation policies and procedures and reports to the Board on the Committee's activities and fair value determinations. The Board monitors the appropriateness of the procedures used in valuing the Fund's investments and ratifies the fair value determinations of the Committee.

The Fund categorizes the inputs to valuation techniques used to value its investments into a disclosure hierarchy consisting of three levels as shown below:

Level 1 – quoted prices in active markets for identical investments
Level 2 – other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, etc.)
Level 3 – unobservable inputs (including the Fund's own assumptions based on the best information available)

Valuation techniques used to value the Fund's investments by major category are as follows:

Debt securities, including restricted securities, are valued based on evaluated prices received from third party pricing vendors or from brokers who make markets in such securities. U.S. government and government agency obligations are valued by pricing vendors who utilize matrix pricing which considers yield or price of bonds of comparable quality, coupon, maturity and type or by broker-supplied prices. When independent prices are unavailable or unreliable, debt securities may be valued utilizing pricing methodologies which consider similar factors that would be used by third party pricing vendors. Debt securities are generally categorized as Level 2 in the hierarchy but may be Level 3 depending on the circumstances.

Investments in open-end mutual funds, including the Fidelity Central Funds, are valued at their closing net asset value (NAV) each business day and are categorized as Level 1 in the hierarchy.

Changes in valuation techniques may result in transfers in or out of an assigned level within the disclosure hierarchy. The aggregate value of investments by input level as of April 30, 2020 is included at the end of the Fund's Schedule of Investments.

Investment Transactions and Income. For financial reporting purposes, the Fund's investment holdings and NAV include trades executed through the end of the last business day of the period. The NAV per share for processing shareholder transactions is calculated as of the close of business of the New York Stock Exchange (NYSE), normally 4:00 p.m. Eastern time and includes trades executed through the end of the prior business day. Gains and losses on securities sold are determined on the basis of identified cost. Income and capital gain distributions from Fidelity Central Funds, if any, are recorded on the ex-dividend date. Interest income is accrued as earned and includes coupon interest and amortization of premium and accretion of discount on debt securities as applicable.

Book-tax differences are primarily due to capital loss carryforwards and losses deferred due to wash sales.

As of period end, the cost and unrealized appreciation (depreciation) in securities, and derivatives if applicable, for federal income tax purposes were as follows:

Gross unrealized appreciation	$1,840,202
Gross unrealized depreciation	(128,096)
Net unrealized appreciation (depreciation)	$1,712,106
Tax Cost	$2,214,216,904

The tax-based components of distributable earnings as of period end were as follows:

Undistributed ordinary income	$5,546,313
Undistributed long-term capital gain	$4
Net unrealized appreciation (depreciation) on securities and other investments	$1,712,106

The tax character of distributions paid was as follows:

	April 30, 2020	April 30, 2019^(a)
Ordinary Income	$27,218,002	$ 13,725,351

(a) For the period August 17, 2018 (commencement of operations) to April 30, 2019.

4. Fees and Other Transactions with Affiliates.

Management Fee. Fidelity Management & Research Company LLC (the investment adviser) and its affiliates provide the Fund with investment management related services for which the Fund does not pay a management fee. Under the management contract, the investment adviser or an affiliate pays all ordinary operating expenses of the Fund, except custody fees, fees and expenses of the independent Trustees, and certain miscellaneous expenses such as proxy and shareholder meeting expenses.

5. Committed Line of Credit.

Certain Funds participate with other funds managed by the investment adviser or an affiliate in a $4.25 billion credit facility (the "line of credit") to be utilized for temporary or emergency purposes to fund shareholder redemptions or for other short-term liquidity purposes. The participating funds have agreed to pay commitment fees on their pro-rata portion of the line of credit, which are reflected in Commitment fees on the Statement of Operations, and are as follows:

	Amount
Fidelity Series Treasury Bill Index Fund	$3,662

During the period, there were no borrowings on this line of credit.

6. Expense Reductions.

Through arrangements with the Fund's custodian, credits realized as a result of certain uninvested cash balances were used to reduce the Fund's expenses by $38.

7. Other.

At the end of the period, mutual funds and accounts managed by the investment adviser or its affiliates were the owners of record of all of the outstanding shares of the Fund.

8. Coronavirus (COVID-19) Pandemic.

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of Fidelity Hereford Street Trust and Shareholders of Fidelity Series Treasury Bill Index Fund

Opinion on the Financial Statements and Financial Highlights

We have audited the accompanying statement of assets and liabilities of Fidelity Series Treasury Bill Index Fund (the "Fund"), a fund of Fidelity Hereford Street Trust, including the schedule of investments, as of April 30, 2020, the related statement of operations for the year then ended, the statement of changes in net assets and the financial highlights for the year then ended and for the period from August 17, 2018 (commencement of operations) to April 30, 2019, and the related notes. In our opinion, the financial statements and financial highlights present fairly, in all material respects, the financial position of the Fund as of April 30, 2020, the results of its operations for the year then ended, and the changes in its net assets and the financial highlights for the year then ended and for the period from August 17, 2018 (commencement of operations) to April 30, 2019, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements and financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on the Fund's financial statements and financial highlights based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Fund in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement, whether due to error or fraud. The Fund is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Fund’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements and financial highlights, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements and financial highlights. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements and financial highlights. Our procedures included confirmation of securities owned as of April 30, 2020, by correspondence with the custodian and brokers; when replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion.

/s/ Deloitte & Touche LLP

Boston, Massachusetts

June 15, 2020

We have served as the auditor of one or more of the Fidelity investment companies since 1999.

Trustees and Officers

The fund’s Statement of Additional Information (SAI) includes more information about the Trustees. To request a free copy, call Fidelity at 1-800-544-8544.

The Trustees operate using a system of committees to facilitate the timely and efficient consideration of all matters of importance to the Trustees, the fund, and fund shareholders and to facilitate compliance with legal and regulatory requirements and oversight of the fund's activities and associated risks. The Board, acting through its committees, has charged FMR and its affiliates with (i) identifying events or circumstances the occurrence of which could have demonstrably adverse effects on the fund's business and/or reputation; (ii) implementing processes and controls to lessen the possibility that such events or circumstances occur or to mitigate the effects of such events or circumstances if they do occur; and (iii) creating and maintaining a system designed to evaluate continuously business and market conditions in order to facilitate the identification and implementation processes described in (i) and (ii) above. Because the day-to-day operations and activities of the fund are carried out by or through FMR, its affiliates, and other service providers, the fund's exposure to risks is mitigated but not eliminated by the processes overseen by the Trustees. While each of the Board's committees has responsibility for overseeing different aspects of the fund's activities, oversight is exercised primarily through the Operations and Audit Committees. In addition, an ad hoc Board committee of Independent Trustees has worked with FMR to enhance the Board's oversight of investment and financial risks, legal and regulatory risks, technology risks, and operational risks, including the development of additional risk reporting to the Board. Appropriate personnel, including but not limited to the fund's Chief Compliance Officer (CCO), FMR's internal auditor, the independent accountants, the fund's Treasurer and portfolio management personnel, make periodic reports to the Board's committees, as appropriate, including an annual review of Fidelity's risk management program for the Fidelity^® funds. The responsibilities of each standing committee, including their oversight responsibilities, are described further under "Standing Committees of the Trustees."

Interested Trustees*:

Correspondence intended for a Trustee who is an interested person may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Abigail P. Johnson (1961)

Year of Election or Appointment: 2009

Trustee

Chairman of the Board of Trustees

Jennifer Toolin McAuliffe (1959)

Year of Election or Appointment: 2016

Trustee

* Determined to be an “Interested Trustee” by virtue of, among other things, his or her affiliation with the trust or various entities under common control with FMR.

Independent Trustees:

Correspondence intended for an Independent Trustee may be sent to Fidelity Investments, P.O. Box 55235, Boston, Massachusetts 02205-5235.

Name, Year of Birth; Principal Occupations and Other Relevant Experience+

Elizabeth S. Acton (1951)

Year of Election or Appointment: 2013

Trustee

Ann E. Dunwoody (1953)

Year of Election or Appointment: 2018

Trustee

John Engler (1948)

Year of Election or Appointment: 2014

Trustee

Robert F. Gartland (1951)

Year of Election or Appointment: 2010

Trustee

Arthur E. Johnson (1947)

Year of Election or Appointment: 2008

Trustee

Chairman of the Independent Trustees

Michael E. Kenneally (1954)

Year of Election or Appointment: 2009

Trustee

Vice Chairman of the Independent Trustees

Marie L. Knowles (1946)

Year of Election or Appointment: 2001

Trustee

Mark A. Murray (1954)

Year of Election or Appointment: 2016

Trustee

Advisory Board Members and Officers:

Correspondence intended for an officer may be sent to Fidelity Investments, 245 Summer Street, Boston, Massachusetts 02210. Officers appear below in alphabetical order.

Name, Year of Birth; Principal Occupation

Elizabeth Paige Baumann (1968)

Year of Election or Appointment: 2017

Anti-Money Laundering (AML) Officer

Craig S. Brown (1977)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Brown also serves as Assistant Treasurer of other funds. Mr. Brown is an employee of Fidelity Investments (2013-present).

John J. Burke III (1964)

Year of Election or Appointment: 2018

Chief Financial Officer

David J. Carter (1973)

Year of Election or Appointment: 2020

Assistant Secretary

Mr. Carter also serves as Assistant Secretary of other funds. Mr. Carter serves as Vice President, Associate General Counsel (2010-present) and is an employee of Fidelity Investments (2005-present).

Jonathan Davis (1968)

Year of Election or Appointment: 2010

Assistant Treasurer

Laura M. Del Prato (1964)

Year of Election or Appointment: 2018

President and Treasurer

Colm A. Hogan (1973)

Year of Election or Appointment: 2016

Assistant Treasurer

Cynthia Lo Bessette (1969)

Year of Election or Appointment: 2019

Secretary and Chief Legal Officer (CLO)

Chris Maher (1972)

Year of Election or Appointment: 2013

Assistant Treasurer

Nancy D. Prior (1967)

Year of Election or Appointment: 2014

Vice President

Kenneth B. Robins (1969)

Year of Election or Appointment: 2020

Chief Compliance Officer

Stacie M. Smith (1974)

Year of Election or Appointment: 2013

Assistant Treasurer

Marc L. Spector (1972)

Year of Election or Appointment: 2016

Deputy Treasurer

Jim Wegmann (1979)

Year of Election or Appointment: 2019

Assistant Treasurer

Mr. Wegmann also serves as Assistant Treasurer of other funds. Mr. Wegmann is an employee of Fidelity Investments (2011-present).

Shareholder Expense Example

The Example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period (November 1, 2019 to April 30, 2020).

Actual Expenses

The first line of the accompanying table provides information about actual account values and actual expenses. You may use the information in this line, together with the amount you invested, to estimate the expenses that you paid over the period. Simply divide your account value by $1,000.00 (for example, an $8,600 account value divided by $1,000.00 = 8.6), then multiply the result by the number in the first line under the heading entitled "Expenses Paid During Period" to estimate the expenses you paid on your account during this period. In addition, the Fund, as a shareholder in the underlying Fidelity Central Funds, will indirectly bear its pro-rata share of the fees and expenses incurred by the underlying Fidelity Central Funds. These fees and expenses are not included in the Fund's annualized expense ratio used to calculate the expense estimate in the table below.

Hypothetical Example for Comparison Purposes

The second line of the accompanying table provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the Fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds. In addition, the Fund, as a shareholder in the underlying Fidelity Central Funds, will indirectly bear its pro-rata share of the fees and expenses incurred by the underlying Fidelity Central Funds. These fees and expenses are not included in the Fund's annualized expense ratio used to calculate the expense estimate in the table below.

	Annualized Expense Ratio-^A	Beginning Account Value November 1, 2019	Ending Account Value April 30, 2020	Expenses Paid During Period-^B November 1, 2019 to April 30, 2020
Actual	- %-^C	$1,000.00	$1,009.70	$--^D
Hypothetical-^E		$1,000.00	$1,024.86	$--^D

^A Annualized expense ratio reflects expenses net of applicable fee waivers.

^B Expenses are equal to the Fund's annualized expense ratio, multiplied by the average account value over the period, multiplied by 182/366 (to reflect the one-half year period).

^C Amount represents less than .005%.

^D Amount represents less than $.005.

^E 5% return per year before expenses

Distributions (Unaudited)

The Board of Trustees of Fidelity Series Treasury Bill Index Fund voted to pay on June 8, 2020, to shareholders of record at the opening of business on June 5, 2020, a distribution of $0.025 per share derived from capital gains realized from sales of portfolio securities.

A total of 99.78% of the dividends distributed during the fiscal year was derived from interest on U.S. Government securities which is generally exempt from state income tax.

The fund will notify shareholders in January 2021 of amounts for use in preparing 2020 income tax returns.

Liquidity Risk Management Program

The Securities and Exchange Commission adopted Rule 22e-4 under the Investment Company Act of 1940 (the Liquidity Rule) to promote effective liquidity risk management throughout the open-end investment company industry, thereby reducing the risk that funds will be unable to meet their redemption obligations and mitigating dilution of the interests of fund shareholders.

The Fund has adopted and implemented a liquidity risk management program pursuant to the Liquidity Rule (the Program) effective December 1, 2018. The Program is reasonably designed to assess and manage the Fund’s liquidity risk and to comply with the requirements of the Liquidity Rule. The Fund’s Board of Trustees (the Board) has designated the Fund’s investment adviser as administrator of the Program. The Fidelity advisers have established a Liquidity Risk Management Committee (the LRM Committee) to manage the Program for each of the Fidelity Funds. The LRM Committee monitors the adequacy and effectiveness of implementation of the Program and on a periodic basis assesses each Fund’s liquidity risk based on a variety of factors including (1) the Fund’s investment strategy, (2) portfolio liquidity and cash flow projections during normal and reasonably foreseeable stressed conditions, (3) shareholder redemptions, (4) borrowings and other funding sources and (5) in the case of exchange-traded funds, certain additional factors including the effect of the Fund’s prices and spreads, market participants, and basket compositions on the overall liquidity of the Fund’s portfolio, as applicable.

In accordance with the Program, each of the Fund’s portfolio investments is classified into one of four liquidity categories described below based on a determination of a reasonable expectation for how long it would take to convert the investment to cash (or sell or dispose of the investment) without significantly changing its market value.

Highly liquid investments – cash or convertible to cash within three business days or less
Moderately liquid investments – convertible to cash in three to seven calendar days
Less liquid investments – can be sold or disposed of, but not settled, within seven calendar days
Illiquid investments – cannot be sold or disposed of within seven calendar days

Liquidity classification determinations take into account a variety of factors including various market, trading and investment-specific considerations, as well as market depth, and generally utilize analysis from a third-party liquidity metrics service.

The Liquidity Rule places a 15% limit on a fund’s illiquid investments and requires funds that do not primarily hold assets that are highly liquid investments to determine and maintain a minimum percentage of the fund’s net assets to be invested in highly liquid investments (highly liquid investment minimum or HLIM). The Program includes provisions reasonably designed to comply with the 15% limit on illiquid investments and for determining, periodically reviewing and complying with the HLIM requirement as applicable.

At a recent meeting of the Fund’s Board of Trustees, the LRM Committee provided a written report to the Board pertaining to the operation, adequacy, and effectiveness of implementation of the Program for the annual period from December 1, 2018 through November 30, 2019. The report concluded that the Program has been implemented and is operating effectively and is reasonably designed to assess and manage the Fund’s liquidity risk.

Fidelity Investments

XSB-ANN-0620
1.9891219.101

Item 2.

Code of Ethics

As of the end of the period, April 30, 2020, Fidelity Hereford Street Trust (the trust) has adopted a code of ethics, as defined in Item 2 of Form N-CSR, that applies to its President and Treasurer and its Chief Financial Officer. A copy of the code of ethics is filed as an exhibit to this Form N-CSR.

Item 3.

Audit Committee Financial Expert

The Board of Trustees of the trust has determined that Elizabeth S. Acton is an audit committee financial expert, as defined in Item 3 of Form N-CSR. Ms. Acton is independent for purposes of Item 3 of Form N-CSR.

Item 4.

Principal Accountant Fees and Services

Fees and Services

The following table presents fees billed by Deloitte & Touche LLP, the member firms of Deloitte Touche Tohmatsu, and their respective affiliates (collectively, “Deloitte Entities”) in each of the last two fiscal years for services rendered to Fidelity Series Treasury Bill Index Fund (the “Fund”):

Services Billed by Deloitte Entities

April 30, 2020 Fees^A


	Audit Fees	Audit-Related Fees	Tax Fees	All Other Fees
Fidelity Series Treasury Bill Index Fund	$36,500	$-	$9,000	$800

April 30, 2019 Fees^A,B


	Audit Fees	Audit-Related Fees	Tax Fees	All Other Fees
Fidelity Series Treasury Bill Index Fund	$32,000	$-	$4,800	$600

^AAmounts may reflect rounding.

^BFidelity Series Treasury Bill Index Fund commenced operations on August 17, 2018.

The following table presents fees billed by PricewaterhouseCoopers LLP (“PwC”) in each of the last two fiscal years for services rendered to Fidelity Flex Government Money

Market Fund, Fidelity Government Money Market Fund, Fidelity Money Market Fund and Fidelity Treasury Only Money Market Fund (the “Funds”):

Services Billed by PwC

April 30, 2020 Fees^A


	Audit Fees	Audit-Related Fees	Tax Fees	All Other Fees
Fidelity Flex Government Money Market Fund	$38,500	$3,200	$2,500	$1,700
Fidelity Government Money Market Fund	$40,900	$3,300	$1,900	$1,800
Fidelity Money Market Fund	$37,000	$3,000	$1,900	$1,700
Fidelity Treasury Only Money Market Fund	$35,700	$2,900	$1,900	$1,600

April 30, 2019 Fees^A


	Audit Fees	Audit-Related Fees	Tax Fees	All Other Fees
Fidelity Flex Government Money Market Fund	$40,000	$3,100	$2,500	$1,800
Fidelity Government Money Market Fund	$48,000	$3,600	$2,000	$2,100
Fidelity Money Market Fund	$39,000	$3,300	$2,900	$1,900
Fidelity Treasury Only Money Market Fund	$37,000	$3,200	$2,900	$1,800

^AAmounts may reflect rounding.

The following table(s) present(s) fees billed by Deloitte Entities and PwC that were required to be approved by the Audit Committee for services that relate directly to the operations and financial reporting of the Fund(s) and that are rendered on behalf of Fidelity Management & Research Company LLC ("FMR") and entities controlling, controlled by, or under common control with FMR (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser) that provide ongoing services to the Fund(s) (“Fund Service Providers”):

Services Billed by Deloitte Entities


	April 30, 2020^A	April 30, 2019^A,B
Audit-Related Fees	$-	$290,000
Tax Fees	$3,000	$5,000
All Other Fees	$-	$-

^A Amounts may reflect rounding.

^BMay include amounts billed prior to the Fidelity Series Treasury Bill Index Fund’s commencement of operations.

Services Billed by PwC


	April 30, 2020^A	April 30, 2019^A
Audit-Related Fees	$8,596,700	$7,890,000
Tax Fees	$17,700	$20,000
All Other Fees	$-	$-

^A Amounts may reflect rounding.

“Audit-Related Fees” represent fees billed for assurance and related services that are reasonably related to the performance of the fund audit or the review of the fund's financial statements and that are not reported under Audit Fees.

“Tax Fees” represent fees billed for tax compliance, tax advice or tax planning that relate directly to the operations and financial reporting of the fund.

“All Other Fees” represent fees billed for services provided to the fund or Fund Service Provider, a significant portion of which are assurance related, that relate directly to the operations and financial reporting of the fund, excluding those services that are reported under Audit Fees, Audit-Related Fees or Tax Fees.

Assurance services must be performed by an independent public accountant.

* * *

The aggregate non-audit fees billed by Deloitte Entities and PwC for services rendered to the Fund(s), FMR (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any Fund Service Provider for each of the last two fiscal years of the Fund(s) are as follows:


Billed By	April 30, 2020^A	April 30, 2019^A,B
Deloitte Entities	$514,400	$710,000
PwC	$13,476,900	$12,410,000

^A Amounts may reflect rounding.

^BMay include amounts billed prior to the Fidelity Series Treasury Bill Index Fund’s commencement of operations.

The trust's Audit Committee has considered non-audit services that were not pre-approved that were provided by Deloitte Entities and PwC to Fund Service Providers to be compatible with maintaining the independence of Deloitte Entities and PwC in its(their) audit of the Fund(s), taking into account representations from Deloitte Entities and PwC, in accordance with Public Company Accounting Oversight Board rules, regarding its independence from the Fund(s) and its(their) related entities and FMR’s review of the appropriateness and permissibility under applicable law of such non-audit services prior to their provision to the Fund(s) Service Providers.

Audit Committee Pre-Approval Policies and Procedures

The trust’s Audit Committee must pre-approve all audit and non-audit services provided by a fund’s independent registered public accounting firm relating to the operations or financial reporting of the fund. Prior to the commencement of any audit or non-audit services to a fund, the Audit Committee reviews the services to determine whether they are appropriate and permissible under applicable law.

The Audit Committee has adopted policies and procedures to, among other purposes, provide a framework for the Committee’s consideration of non-audit services by the audit firms that audit the Fidelity funds. The policies and procedures require that any non-audit service provided by a fund audit firm to a Fidelity fund and any non-audit service provided by a fund auditor to a Fund Service Provider that relates directly to the operations and financial reporting of a Fidelity fund (“Covered Service”) are subject to approval by the Audit Committee before such service is provided.

All Covered Services must be approved in advance of provision of the service either: (i) by formal resolution of the Audit Committee, or (ii) by oral or written approval of the service by the Chair of the Audit Committee (or if the Chair is unavailable, such other member of the Audit Committee as may be designated by the Chair to act in the Chair’s absence). The approval contemplated by (ii) above is permitted where the Treasurer determines that action on such an engagement is necessary before the next meeting of the Audit Committee.

Non-audit services provided by a fund audit firm to a Fund Service Provider that do not relate directly to the operations and financial reporting of a Fidelity fund are reported to the Audit Committee periodically.

Non-Audit Services Approved Pursuant to Rule 2-01(c)(7)(i)(C) and (ii) of Regulation S-X (“De Minimis Exception”)

There were no non-audit services approved or required to be approved by the Audit Committee pursuant to the De Minimis Exception during the Fund’s(s’) last two fiscal

years relating to services provided to (i) the Fund(s) or (ii) any Fund Service Provider that relate directly to the operations and financial reporting of the Fund(s).

Item 5.

Audit Committee of Listed Registrants

Not applicable.

Item 6.

Investments

(a)

Not applicable.

(b)

Not applicable.

Item 7.

Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies

Not applicable.

Item 8.

Portfolio Managers of Closed-End Management Investment Companies

Not applicable.

Item 9.

Purchase of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers

Not applicable.

Item 10.

Submission of Matters to a Vote of Security Holders

There were no material changes to the procedures by which shareholders may recommend nominees to the trust’s Board of Trustees.

Item 11.

Controls and Procedures

(a)(i) The President and Treasurer and the Chief Financial Officer have concluded that the trust’s disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act) provide reasonable assurances that material information relating to the trust is made known to them by the appropriate persons, based on their evaluation of these controls and procedures as of a date within 90 days of the filing date of this report.

(a)(ii) There was no change in the trust’s internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act) that occurred during the period covered by this report that has materially affected, or is reasonably likely to materially affect, the trust’s internal control over financial reporting.

Item 12.

Disclosure of Securities Lending Activities for Closed-End Management

Investment Companies

Not applicable.

Item 13.

Exhibits


(a)	(1)	Code of Ethics pursuant to Item 2 of Form N-CSR is filed and attached hereto as EX-99.CODE ETH.
(a)	(2)	Certification pursuant to Rule 30a-2(a) under the Investment Company Act of 1940 (17 CFR 270.30a-2(a)) is filed and attached hereto as Exhibit 99.CERT.
(a)	(3)	Not applicable.
(b)		Certification pursuant to Rule 30a-2(b) under the Investment Company Act of 1940 (17 CFR 270.30a-2(b)) is furnished and attached hereto as Exhibit 99.906CERT.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Fidelity Hereford Street Trust


By:	/s/Laura M. Del Prato
	Laura M. Del Prato
	President and Treasurer

Date:	June 19, 2020

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.


By:	/s/Laura M. Del Prato
	Laura M. Del Prato
	President and Treasurer

Date:	June 19, 2020


By:	/s/John J. Burke III
	John J. Burke III
	Chief Financial Officer

Date:	June 19, 2020