03.31 FIMM Funds Class 4 Combo PRO-06 | Prime Money Market Portfolio

<p style="font: bold 20pt Arial, Helvetica, sans-serif;">Fund Summary</p><p style="font: normal 12pt Arial, Helvetica, sans-serif;"><b>Fund/Class</b>:<br/><b>Prime Money Market Portfolio</b>/IV</p>

<font style="font: bold 16pt Arial, Helvetica, sans-serif;">Investment Objective</font>

The fund seeks to obtain as high a level of current income as is consistent with the preservation of principal and liquidity within the limitations prescribed for the fund.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Fee Table</b></font>

The following table describes the fees and expenses that may be incurred when you buy and hold shares of the fund.

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Shareholder fees</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px"></p>

Shareholder Fees {- Prime Money Market Portfolio}	03.31 FIMM Funds Class 4 Combo PRO-06 Prime Money Market Portfolio USD ($)
(fees paid directly from your investment)	none

<p style="font: bold 11pt Arial, sans-serif; margin-bottom: 0px;">Annual Operating Expenses</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">(expenses that you pay each year as a % of the value of your investment)</p>

Annual Operating Expenses {- Prime Money Market Portfolio}	03.31 FIMM Funds Class 4 Combo PRO-06 Prime Money Market Portfolio Prime Money Market Portfolio-Class IV
Management fee	0.14%
Distribution and/or Service (12b-1) fees	0.50%
Other expenses	0.07%
Total annual operating expenses	0.71%
Fee waiver and/or expense reimbursement	0.03%	[1]
Total annual operating expenses after fee waiver and/or expense reimbursement	0.68%

This example helps compare the cost of investing in the fund with the cost of investing in other funds.

Let's say, hypothetically, that the annual return for shares of the fund is 5% and that your shareholder fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:

<p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">Sell All Shares</p>

Expense Example {- Prime Money Market Portfolio}	03.31 FIMM Funds Class 4 Combo PRO-06 Prime Money Market Portfolio Prime Money Market Portfolio-Class IV USD ($)
1 year	$ 69
3 years	223
5 years	391
10 years	$ 879

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Strategies</b></font>

• Investing in U.S. dollar-denominated money market securities of domestic and foreign issuers, U.S. Government securities, and repurchase agreements.

• Potentially entering into reverse repurchase agreements.

• Investing more than 25% of total assets in the financial services industries.

• Investing in compliance with industry-standard regulatory requirements for money market funds for the quality, maturity, liquidity, and diversification of investments.

Although the fund is a money market fund, it will price and transact at a "floating" net asset value (NAV) that will fluctuate based on changes in the value of the fund's investments.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Principal Investment Risks</b></font>

• Interest Rate Changes. Interest rate increases can cause the price of a money market security to decrease.

• Floating NAV. The fund does not maintain a constant NAV per share of $1.00. The value of the fund's shares will be calculated to four decimal places and will vary as a result of changes in the value of the securities in which the fund invests.

• Foreign Exposure. Entities located in foreign countries can be affected by adverse political, regulatory, market, or economic developments in those countries.

• Financial Services Concentration. Changes in government regulation and interest rates and economic downturns can have a significant negative effect on issuers in the financial services sector, including the price of their securities or their ability to meet their payment obligations.

• Issuer-Specific Changes. A decline in the credit quality of an issuer or a provider of credit support or a maturity-shortening structure for a security can cause the price of a money market security to decrease.

You could lose money by investing in the fund. Because the share price of the fund will fluctuate, when you sell your shares they may be worth more or less than what you originally paid for them. The fund may impose a fee upon the sale of your shares or may temporarily suspend your ability to sell shares if the fund's liquidity falls below required minimums because of market conditions or other factors. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Fidelity Investments and its affiliates, the fund’s sponsor, have no legal obligation to provide financial support to the fund, and you should not expect that the sponsor will provide financial support to the fund at any time.

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Performance</b></font>

The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year. Past performance is not an indication of future performance.

Visit institutional.fidelity.com for more recent performance information.

<p style="font:bold 11pt Arial, sans-serif; margin-bottom: 0px;">Year-by-Year Returns</p><p style="font: bold 9pt Arial, sans-serif; margin-top: 0px">Calendar Years</p>

During the periods shown in the chart:	Returns	Quarter ended
Highest Quarter Return	0.43%	December 31, 2018
Lowest Quarter Return	0.00%	March 31, 2015
Year-to-Date Return	0.49%	March 31, 2019

<font style="font: bold 16pt Arial, Helvetica, sans-serif;"><b>Average Annual Returns</b></font>

For the periods ended December 31, 2018

Average Annual Total Returns{- Prime Money Market Portfolio}	Past 1 year	Past 5 years	Past 10 years
03.31 FIMM Funds Class 4 Combo PRO-06 | Prime Money Market Portfolio | Prime Money Market Portfolio-Class IV | Return Before Taxes	1.42%	0.42%	0.24%

[1] Fidelity Management & Research Company (FMR) has contractually agreed to reimburse Class IV of the fund to the extent that total operating expenses (excluding interest, certain taxes, fees and expenses of the Independent Trustees, proxy and shareholder meeting expenses, extraordinary expenses, and acquired fund fees and expenses, if any, as well as non-operating expenses such as brokerage commissions and fees and expenses associated with the fund's securities lending program, if applicable), as a percentage of its average net assets, exceed 0.68% (the Expense Cap). If at any time during the current fiscal year expenses for Class IV of the fund fall below the Expense Cap, FMR reserves the right to recoup through the end of the fiscal year any expenses that were reimbursed during the current fiscal year up to, but not in excess of, the Expense Cap. This arrangement will remain in effect through July 31, 2020. FMR may not terminate this arrangement before the expiration date without the approval of the Board of Trustees and may extend it in its discretion after that date.