N-CSR

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 811-22033

MFS SERIES TRUST XIV

(Exact name of registrant as specified in charter)

111 Huntington Avenue, Boston, Massachusetts 02199

(Address of principal executive offices) (Zip code)

Christopher R. Bohane

Massachusetts Financial Services Company

111 Huntington Avenue

Boston, Massachusetts 02199

(Name and address of agents for service)

Registrant’s telephone number, including area code: (617) 954-5000

Date of fiscal year end: August 31

Date of reporting period: August 31, 2017

ITEM 1. REPORTS TO STOCKHOLDERS.

ANNUAL REPORT

August 31, 2017

MFS® INSTITUTIONAL MONEY MARKET PORTFOLIO

IMM-ANN

MFS® INSTITUTIONAL MONEY MARKET PORTFOLIO

CONTENTS

Letter from the Executive Chairman	1
Portfolio composition	2
Performance summary	3
Expense table	4
Portfolio of investments	5
Statement of assets and liabilities	9
Statement of operations	10
Statements of changes in net assets	11
Financial highlights	12
Notes to financial statements	13
Report of independent registered public accounting firm	18
Results of shareholder meeting	19
Trustees and officers	20
Board review of investment advisory agreement	26
Proxy voting policies and information	29
Quarterly portfolio disclosure	29
Further information	29
Information about fund contracts and legal claims	30
Federal tax information	30
MFS® privacy notice	31
Contact information    back cover

The report is prepared for the general information of shareholders.

It is authorized for distribution to prospective investors only when preceded or accompanied by a current prospectus.

NOT FDIC INSURED • MAY LOSE VALUE • NO BANK GUARANTEE

LETTER FROM THE EXECUTIVE CHAIRMAN

Dear Shareholders:

Despite policy uncertainty accompanying a new presidential administration in the United States and unease over ongoing Brexit negotiations, most markets have proved

resilient. U.S. share prices have reached new highs in recent months although the U.S. Federal Reserve has continued to gradually hike interest rates. However, rates in most developed markets remain very low, with major non-U.S. central banks just beginning to contemplate curbing accommodative monetary policies.

Globally, we’ve experienced a year-long synchronized upturn in economic growth. Despite better growth, there are few immediate signs of worrisome inflation amid muted wage gains around the world. Europe has benefited from diminishing event risks as populist challengers fell short of upsetting establishment

candidates in both the Dutch and French elections. Emerging market economies have been boosted in part by a weaker U.S. dollar and are recovering despite lingering concerns over the potential for restrictive U.S. trade policies that could hamper global trade growth. Looking ahead, markets will have to contend with issues involving geopolitical hot spots on the Korean peninsula and in the Middle East.

At MFS®, we believe time is an asset. A patient, long-term approach to investing can have a powerful impact on decision making and outcomes. Time arbitrage, as we call it, comes down to having the conviction and discipline to allow enough time for good investment ideas to play out. In our view, such an approach, along with the professional guidance of a financial advisor, will help you reach your investment objectives.

Respectfully,

Robert J. Manning

Executive Chairman

MFS Investment Management

October 17, 2017

The opinions expressed in this letter are subject to change and may not be relied upon for investment advice. No forecasts can be guaranteed.

1

PORTFOLIO COMPOSITION

Portfolio structure (u)

Composition including fixed income credit quality (a)(u)
A-1+	26.9%
A-1	71.6%
A-2	1.5%
Not Rated	0.0%
Other Assets Less Liabilities (o)	0.0%

Maturity breakdown (u)
0 - 7 days	29.0%
8 - 29 days	45.5%
30 - 59 days	12.6%
60 - 89 days	8.6%
90 - 365 days	4.3%
Other Assets Less Liabilities (o)	0.0%

(a) Ratings are assigned to portfolio securities utilizing ratings from Moody’s, Fitch, and Standard & Poor’s rating agencies and applying the following hierarchy: If all three agencies provide a rating, the middle rating (after dropping the highest and lowest ratings) is assigned; if two of the three agencies rate a security, the lower of the two is assigned. Ratings are shown in the S&P scale. All ratings are subject to change. The fund is not rated by these agencies.

(o) Less than 0.1%.

(u) For purposes of this presentation, accrued interest, where applicable, is included.

Percentages are based on net assets as of August 31, 2017.

The portfolio is actively managed and current holdings may be different.

2

PERFORMANCE SUMMARY THROUGH 8/31/17

Total returns as well as the current 7-day yield have been provided for the applicable time periods. Performance results reflect the percentage change in net asset value, including the reinvestment of any dividends and capital gains distributions. (See Notes to Performance Summary.)

Performance data shown represents past performance and is no guarantee of future results. The net asset value of the fund’s shares is determined each day the NYSE is open for trading as of 1:00 p.m., Eastern time. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. The performance shown does not reflect the deduction of taxes, if any, that a shareholder would pay on fund distributions or the redemption of fund shares.

Inception	1-Year Total Return	Current 7-day yield
3/19/07	0.69%	1.11%

Yields quoted are based on the latest seven days ended as of August 31, 2017, with dividends annualized. The yield quotations more closely reflect the current earnings of the fund than the total return quotations. Shares of the fund can be purchased at net asset value without a sales charge.

Notes to Performance Summary

Performance results reflect any applicable expense subsidies, waivers and adjustments in effect during the periods shown. Without such subsidies and waivers the fund’s performance results would be less favorable. Please see the prospectus and financial statements for complete details. All results are historical and assume the reinvestment of any dividends and capital gain distributions.

3

EXPENSE TABLE

Fund expenses borne by the shareholders during the period, March 1, 2017 through August 31, 2017

As a shareholder of the fund, you incur ongoing costs, including 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 March 1, 2017 through August 31, 2017.

Actual Expenses

The first line of the following 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 (for example, an $8,600 account value divided by $1,000 = 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.

Hypothetical Example for Comparison Purposes

The second line of the following 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.

Please note that the expenses shown in the table are meant to highlight your ongoing costs only and do not reflect any transactional costs, such as sales charges (loads). 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. In addition, if these transactional costs were included, your costs would have been higher.

	Annualized Expense Ratio	Beginning Account Value 3/01/17	Ending Account Value 8/31/17	Expenses Paid During Period (p) 3/01/17-8/31/17
Actual	0.01%	$1,000.00	$1,004.47	$0.05
Hypothetical (h)	0.01%	$1,000.00	$1,025.16	$0.05

(h) 5% fund return per year before expenses.

(p) “Expenses Paid During Period” are equal to the fund’s annualized expense ratio, as shown above, multiplied by the average account value over the period, multiplied by 184/365 (to reflect the one-half year period).

4

PORTFOLIO OF INVESTMENTS

8/31/17

The Portfolio of Investments is a complete list of all securities owned by your fund. It is categorized by broad-based asset classes.

Certificates of Deposit - 14.4%
Issuer	Shares/Par		Value ($)
Major Banks - 11.4%
Bank of Montreal/Chicago Branch, 1.2%, due 9/12/2017	$	96,300,000	$	96,300,294
Bank of Montreal/Chicago Branch, 1.2%, due 9/14/2017		50,000,000		50,000,121
Bank of Montreal/Chicago Branch, 1.2%, due 10/2/2017		100,800,000		100,797,935
Canadian Imperial Bank of Commerce/New York Branch, 1.16%, due 9/20/2017		47,790,000		47,789,507
Canadian Imperial Bank of Commerce/New York Branch, 1.16%, due 9/21/2017		133,170,000		133,168,649
Canadian Imperial Bank of Commerce/New York Branch, 1.19%, due 9/21/2017		54,900,000		54,900,390
Toronto Dominion Holdings (USA), Inc., 1.2%, due 9/18/2017		77,250,000		77,250,396
Toronto Dominion Holdings (USA), Inc., 1.25%, due 11/15/2017		84,637,000		84,632,241
Toronto Dominion Holdings (USA), Inc., 1.3%, due 11/21/2017		25,000,000		25,000,912
Toronto Dominion Holdings (USA), Inc., 1.33%, due 12/19/2017		45,700,000		45,699,904
			$	715,540,349
Other Banks & Diversified Financials - 3.0%
Mizuho Corporate Bank (USA)/New York Branch, 1.18%, due 9/8/2017	$	52,527,000	$	52,527,212
Mizuho Corporate Bank (USA)/New York Branch, 1.18%, due 9/13/2017		85,930,000		85,930,377
Mizuho Corporate Bank (USA)/New York Branch, 1.26%, due 12/4/2017		50,000,000		49,997,759
			$	188,455,348
Total Certificates of Deposit (Identified Cost, $904,004,000)			$	903,995,697
Commercial Paper (y) - 54.5%
Automotive - 1.6%
American Honda Finance Corp., 1.231%, due 9/19/2017	$	43,300,000	$	43,274,108
American Honda Finance Corp., 1.243%, due 11/21/2017		40,000,000		39,892,580
Toyota Motor Credit Corp., 1.11%, due 9/12/2017		20,000,000		19,992,740
			$	103,159,428
Business Services - 2.6%
Cisco Systems, Inc., 1.16%, due 9/6/2017 (t)	$	96,000,000	$	95,982,576
Cisco Systems, Inc., 1.172%, due 10/18/2017 (t)		64,915,000		64,818,406
			$	160,800,982
Chemicals - 0.8%
3M Co., 1.07%, due 9/5/2017 (t)	$	50,000,000	$	49,992,445

5

Portfolio of Investments – continued

Issuer	Shares/Par		Value ($)
Commercial Paper (y) - continued
Computer Software - Systems - 3.8%
Apple, Inc., 1.111%, due 9/15/2017 (t)	$	84,000,000	$	83,961,500
Apple, Inc., 1.121%, due 9/22/2017 (t)		25,000,000		24,983,118
Apple, Inc., 1.161%, due 10/10/2017 (t)		65,900,000		65,818,503
Apple, Inc., 1.161%, due 10/11/2017 (t)		65,000,000		64,917,533
			$	239,680,654
Conglomerates - 4.9%
Emerson Electric Co., 1.07%, due 9/11/2017 (t)	$	35,000,000	$	34,987,969
Emerson Electric Co., 1.07%, due 9/14/2017 (t)		33,510,000		33,495,287
Siemens Captal Corp., 1.16%, due 9/1/2017 (t)		109,280,000		109,276,715
Siemens Captal Corp., 1.119%, due 9/6/2017 (t)		130,434,000		130,410,326
			$	308,170,297
Consumer Products - 6.4%
Colgate-Palmolive Co., 1.07%, due 9/5/2017 (t)	$	100,000,000	$	99,984,889
Colgate-Palmolive Co., 1.07%, due 9/6/2017 (t)		48,500,000		48,491,197
Colgate-Palmolive Co., 1.07%, due 9/8/2017 (t)		20,000,000		19,995,151
Colgate-Palmolive Co., 1.07%, due 9/12/2017 (t)		14,000,000		13,994,885
Procter & Gamble Co., 1.081%, due 9/25/2017 (t)		100,000,000		99,923,125
Procter & Gamble Co., 1.081%, due 9/26/2017 (t)		45,750,000		45,713,423
Procter & Gamble Co., 1.081%, due 9/27/2017 (t)		75,000,000		74,937,675
			$	403,040,345
Electrical Equipment - 3.5%
General Electric Co., 1.121%, due 9/18/2017	$	90,249,000	$	90,199,183
General Electric Co., 0%, due 9/1/2017		79,022,000		79,019,702
General Electric Co., 1.121%, due 9/20/2017		52,750,000		52,717,559
			$	221,936,444
Energy - Integrated - 7.7%
Chevron Corp., 1.09%, due 9/14/2017 (t)	$	50,000,000	$	49,978,864
Chevron Corp., 1.081%, due 9/20/2017 (t)		190,000,000		189,884,522
Exxon Mobil Corp., 1.05%, due 9/5/2017		50,000,000		49,992,695
Exxon Mobil Corp., 1.05%, due 9/6/2017		50,000,000		49,991,200
Exxon Mobil Corp., 1.09%, due 9/14/2017		70,000,000		69,970,410
Exxon Mobil Corp., 1.121%, due 10/2/2017		70,000,000		69,931,431
			$	479,749,122
Food & Beverages - 6.5%
Coca-Cola Co., 1.101%, due 9/18/2017 (t)	$	20,000,000	$	19,988,980
Coca-Cola Co., 1.182%, due 11/1/2017 (t)		25,000,000		24,951,649
Coca-Cola Co., 1.233%, due 11/7/2017 (t)		28,950,000		28,888,153
Coca-Cola Co., 1.233%, due 11/17/2017 (t)		87,141,000		86,925,006
PepsiCo, Inc., 1.04%, due 9/11/2017 (t)		107,897,000		107,859,910

6

Portfolio of Investments – continued

Issuer	Shares/Par		Value ($)
Commercial Paper (y) - continued
Food & Beverages - continued
PepsiCo, Inc., 1.041%, due 9/22/2017 (t)	$	75,000,000	$	74,947,979
PepsiCo, Inc., 1.091%, due 10/6/2017 (t)		15,000,000		14,982,870
PepsiCo, Inc., 1.092%, due 10/17/2017 (t)		50,000,000		49,925,192
			$	408,469,739
Other Banks & Diversified Financials - 2.4%
National Bank of Canada, 1.314%, due 11/17/2017 (t)	$	150,000,000	$	149,596,350
Pharmaceuticals - 10.3%
Johnson & Johnson, 1.101%, due 9/18/2017 (t)	$	115,800,000	$	115,736,194
Johnson & Johnson, 1.111%, due 9/26/2017 (t)		100,000,000		99,920,050
Johnson & Johnson, 1.091%, due 10/2/2017 (t)		11,548,000		11,536,596
Johnson & Johnson, 1.132%, due 10/23/2017 (t)		20,450,000		20,416,341
Novartis Finance Corp., 1.13%, due 9/7/2017 (t)		67,900,000		67,885,609
Novartis Finance Corp., 1.12%, due 9/8/2017 (t)		35,800,000		35,791,321
Novartis Finance Corp., 1.11%, due 9/12/2017 (t)		30,000,000		29,989,040
Novartis Finance Corp., 1.11%, due 9/14/2017 (t)		20,000,000		19,991,452
Novartis Finance Corp., 1.151%, due 9/25/2017 (t)		20,000,000		19,984,625
Sanofi, 1.201%, due 9/15/2017 (t)		150,000,000		149,931,251
Sanofi, 1.211%, due 9/22/2017 (t)		75,000,000		74,949,354
			$	646,131,833
Retailers - 4.0%
Wal-Mart Stores, Inc., 1.12%, due 9/5/2017 (t)	$	153,225,000	$	153,201,845
Wal-Mart Stores, Inc., 1.093%, due 9/11/2017 (t)		59,135,000		59,115,215
Wal-Mart Stores, Inc., 1.12%, due 9/13/2017 (t)		23,630,000		23,620,631
Wal-Mart Stores, Inc., 1.101%, due 9/18/2017 (t)		11,670,000		11,663,570
			$	247,601,261
Total Commercial Paper (Identified Cost, $3,418,371,081)			$	3,418,328,900
U.S. Government Agencies and Equivalents (y) - 29.6%
Federal Home Loan Bank, 0.993%, due 9/1/2017	$	117,800,000	$	117,800,000
Federal Home Loan Bank, 1.01%, due 9/5/2017		21,991,000		21,988,557
Federal Home Loan Bank, 0.974%, due 9/8/2017		84,687,000		84,670,533
Federal Home Loan Bank, 0.99%, due 9/11/2017		50,000,000		49,986,111
Federal Home Loan Bank, 1.02%, due 9/12/2017		44,811,000		44,797,308
Federal Home Loan Bank, 0.996%, due 9/26/2017		10,699,000		10,691,570
Federal Home Loan Bank, 1.008%, due 9/27/2017		205,000,000		204,851,944
Federal Home Loan Bank, 1.006%, due 10/2/2017		15,324,000		15,310,672
Federal Home Loan Bank, 1.021%, due 10/25/2017		100,000,000		99,848,500
Federal National Mortgage Association, 0.93%, due 9/5/2017		100,000,000		99,988,889
Federal National Mortgage Association, 0.93%, due 9/11/2017		125,000,000		124,965,278
Freddie Mac, 0.991%, due 9/25/2017		18,900,000		18,887,400

7

Portfolio of Investments – continued

Issuer	Shares/Par		Value ($)
U.S. Government Agencies and Equivalents (y) - continued
U.S. Treasury Bill, 0.952%, due 9/7/2017	$	354,300,000	$	354,247,592
U.S. Treasury Bill, 0.947%, due 9/14/2017		116,026,000		115,989,129
U.S. Treasury Bill, 1.031%, due 10/12/2017		150,000,000		149,811,442
U.S. Treasury Bill, 1.017%, due 10/19/2017		65,520,000		65,422,485
U.S. Treasury Bill, 0.957%, due 11/2/2017		100,000,000		99,828,639
U.S. Treasury Bill, 1.053%, due 12/7/2017		125,000,000		124,672,709
U.S. Treasury Bill, 1.119%, due 2/15/2018		51,100,000		50,850,508
Total U.S. Government Agencies and Equivalents (Identified Cost, $1,854,591,390)			$	1,854,609,266
Repurchase Agreements - 1.5%
Goldman Sachs Repurchase Agreement, 1.05%, date 8/31/2017, due 9/01/2017, total to be received $71,773,065 (secured by U.S. Treasury and Federal Agency obligations valued at $73,206,501 in an individually traded account), at Cost and Value	$	71,771,000	$	71,771,000
JPMorgan Chase & Co. Repurchase Agreement, 1.04%, date 8/31/2017, due 9/01/2017, total to be received $25,000,712 (secured by U.S. Treasury obligations valued at $25,504,822 in an individually traded account), at Cost and Value		25,000,000		25,000,000
Total Repurchase Agreements (Identified Cost, $96,771,000)			$	96,771,000
Other Assets, Less Liabilities - 0.0%				461,304
Net Assets - 100.0%			$	6,274,166,167

(t) Security exempt from registration with the U.S. Securities and Exchange Commission under Section 4(2) of the Securities Act of 1933.

(y) The rate shown represents an annualized yield at time of purchase.

See Notes to Financial Statements

8

Financial Statements

STATEMENT OF ASSETS AND LIABILITIES

At 8/31/17

This statement represents your fund’s balance sheet, which details the assets and liabilities comprising the total value of the fund.

Assets
Investments in unaffiliated issuers, at value (identified cost, $6,273,737,471)	$6,273,704,863
Cash	31
Interest receivable	598,119
Other assets	4,680
Total assets	$6,274,307,693
Liabilities
Payable to affiliates
Investment adviser	$96
Shareholder servicing costs	297
Accrued expenses and other liabilities	141,133
Total liabilities	$141,526
Net assets	$6,274,166,167
Net assets consist of
Paid-in capital	$6,274,212,960
Unrealized appreciation (depreciation)	(32,608	)
Accumulated net realized gain (loss)	(14,185	)
Net assets	$6,274,166,167
Shares of beneficial interest outstanding	6,274,324,440
Net asset value per share (net assets of $6,274,166,167 / 6,274,324,440 shares of beneficial interest outstanding)	$1.0000

See Notes to Financial Statements

9

Financial Statements

STATEMENT OF OPERATIONS

Year ended 8/31/17

This statement describes how much your fund earned in investment income and accrued in expenses. It also describes any gains and/or losses generated by fund operations.

Net investment income (loss)
Interest income	$37,800,963
Expenses
Shareholder servicing costs	$965
Administrative services fee	17,500
Insurance fee	26,661
Custodian fee	254,773
Shareholder communications	6,339
Audit and tax fees	33,074
Legal fees	54,961
Commitment fee	35,618
Miscellaneous	32,677
Total expenses	$462,568
Fees paid indirectly	(8,351	)
Net expenses	$454,217
Net investment income (loss)	$37,346,746
Realized and unrealized gain (loss)
Realized gain (loss) on unaffiliated issuers (identified cost basis)	$(14,146	)
Change in unrealized appreciation (depreciation) on unaffiliated issuers	$(137,424	)
Net realized and unrealized gain (loss)	$(151,570	)
Change in net assets from operations	$37,195,176

See Notes to Financial Statements

10

Financial Statements

STATEMENTS OF CHANGES IN NET ASSETS

These statements describe the increases and/or decreases in net assets resulting from operations, any distributions, and any shareholder transactions.

	Year ended
	8/31/17			8/31/16
Change in net assets
From operations
Net investment income (loss)		$37,346,746			$12,658,614
Net realized gain (loss) on investments		(14,146	)		3,915
Net unrealized gain (loss) on investments		(137,424	)		104,816
Change in net assets from operations		$37,195,176			$12,767,345
Distributions declared to shareholders
From net investment income		$(37,346,746	)		$(12,658,614	)
Change in net assets from fund share transactions		$1,652,060,227			$(848,170,413	)
Contribution from adviser		$—			$20,272
Total change in net assets		$1,651,908,657			$(848,041,410	)
Net assets
At beginning of period		4,622,257,510			5,470,298,920
At end of period		$6,274,166,167			$4,622,257,510

See Notes to Financial Statements

11

Financial Statements

FINANCIAL HIGHLIGHTS

The financial highlights table is intended to help you understand the fund’s financial performance for the past 5 years. Certain information reflects financial results for a single fund share. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the fund share class (assuming reinvestment of all distributions) held for the entire period.

	Year ended
	8/31/17			8/31/16			8/31/15			8/31/14			8/31/13
Net asset value, beginning of period		$1.0000			$1.0000			$1.00			$1.00			$1.00
Income (loss) from investment operations
Net investment income (loss) (d)		$0.0071			$0.0027			$0.00	(w)		$0.00	(w)		$0.00	(w)
Net realized and unrealized gain (loss) on investments		(0.0002	)		0.0001			0.00	(w)		0.00	(w)		0.00	(w)
Total from investment operations		$0.0069			$0.0028			$0.00	(w)		$0.00	(w)		$0.00	(w)
Less distributions declared to shareholders
From net investment income		$(0.0069	)		$(0.0028	)		$(0.00	)(w)		$(0.00	)(w)		$(0.00	)(w)
Contribution from adviser		$—			$(0.0000	)(w)		$—			$—			$—
Net asset value, end of period		$1.0000			$1.0000			$1.00			$1.00			$1.00
Total return (%) (r)		0.69			0.28			0.10			0.09			0.14
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)		0.01			0.01			0.01			0.01			0.01
Expenses after expense reductions (f)		0.01			0.01			0.01			0.01			0.01
Net investment income (loss)		0.71			0.27			0.10			0.09			0.13
Net assets at end of period (000 omitted)		$6,274,166			$4,622,258			$5,470,299			$5,284,981			$4,629,640

Effective August 1, 2016, the fund no longer seeks to maintain a stable share price. The value of the fund’s shares are calculated to four decimal places and will vary reflecting the value of the fund’s investments.

(d) Per share data is based on average shares outstanding.

(f) Ratios do not reflect reductions from fees paid indirectly, if applicable.

(r) Certain expenses have been reduced without which performance would have been lower.

(w) Per share amount was less than $0.0001 or, prior to 2016, $0.01.

See Notes to Financial Statements

12

NOTES TO FINANCIAL STATEMENTS

(1) Business and Organization

MFS Institutional Money Market Portfolio (the fund) is a diversified series of MFS Series Trust XIV (the trust). The trust is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-end management investment company. This fund is available only to certain U.S. registered investment companies managed by MFS. MFS does not receive a management fee from this fund.

The fund is an investment company and accordingly follows the investment company accounting and reporting guidance of the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946 Financial Services – Investment Companies.

On July 23, 2014, the U.S. Securities and Exchange Commission adopted amendments to its money market fund regulations. Under the amendments, the fund is considered an “institutional money market fund” and is required to value its portfolio securities at market value and sell and redeem shares based on a floating net asset value. The fund also has the ability to impose a liquidity fee or temporarily suspend redemptions. Effective August 1, 2016, the fund no longer seeks to maintain a stable share price. The value of the fund’s shares are calculated to four decimal places and will vary reflecting the value of the fund’s investments.

(2) Significant Accounting Policies

General – The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in net assets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the fund’s Statement of Assets and Liabilities through the date that the financial statements were issued.

In October 2016, the Securities and Exchange Commission (SEC) released its Final Rule on Investment Company Reporting Modernization (the “Rule”). The Rule, which introduced two new regulatory reporting forms for investment companies – Form N-PORT and Form N-CEN – also contained amendments to Regulation S-X which impact financial statement presentation, particularly the presentation of derivative investments, for all reporting periods ending after August 1, 2017. The fund has adopted the Rule’s Regulation S-X amendments and believes that the fund’s financial statements are in compliance with those amendments.

Balance Sheet Offsetting – The fund’s accounting policy with respect to balance sheet offsetting is that, absent an event of default by the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) Master Agreement does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. The fund’s right to setoff may be restricted

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Notes to Financial Statements – continued

or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreement counterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund’s Significant Accounting Policies note under the captions for each of the fund’s in-scope financial instruments and transactions.

Investment Valuations – Debt instruments are generally valued at an evaluated or composite bid as provided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. The Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund’s investments (including any fair valuation) to the adviser pursuant to valuation policies and procedures approved by the Board. If the adviser determines that reliable market quotations are not readily available, investments are valued at fair value as determined in good faith by the adviser in accordance with such procedures under the oversight of the Board. Under the fund’s valuation policies and procedures, market quotations are not considered to be readily available for most types of debt instruments. These investments are generally valued at fair value based on information from third-party pricing services.

Various inputs are used in determining the value of the fund’s assets or liabilities. These inputs are categorized into three broad levels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an investment’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. The fund’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identical assets or liabilities. Level 2 includes other significant observable market-based inputs (including quoted prices for similar securities, interest rates, prepayment speed, and credit risk). Level 3 includes unobservable inputs, which may include the adviser’s own assumptions in determining the fair value of investments. The following is a summary of the levels used as of August 31, 2017 in valuing the fund’s assets or liabilities:

Financial Instruments	Level 1		Level 2		Level 3		Total
Short-Term Securities		$—		$6,273,704,863		$—		$6,273,704,863

For further information regarding security characteristics, see the Portfolio of Investments.

Repurchase Agreements – The fund enters into repurchase agreements under the terms of Master Repurchase Agreements with approved counterparties. Each repurchase agreement is recorded at cost. The fund requires that the securities collateral in a repurchase transaction be transferred to a custodian. The fund monitors, on a daily basis, the value of the collateral to ensure that its value, including accrued interest, is greater than amounts owed to the fund under each such repurchase agreement. Upon an event of default under a Master Repurchase Agreement, the non-defaulting party may close out all transactions traded under such agreement and net amounts owed under each transaction to one net amount payable by one party to the other. Absent an event of default, the Master Repurchase Agreement does not

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Notes to Financial Statements – continued

result in an offset of reported amounts of assets and liabilities in the Statement of Assets and Liabilities across transactions between the fund and the applicable counterparty. At period end, the fund had investments in repurchase agreements with a gross value of $96,771,000 included in investments in the Statement of Assets and Liabilities. The value of the related collateral exceeded the value of the repurchase agreements at period end.

Indemnifications – Under the fund’s organizational documents, its officers and Trustees may be indemnified against certain liabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, the fund enters into agreements with service providers that may contain indemnification clauses. The fund’s maximum exposure under these agreements is unknown as this would involve future claims that may be made against the fund that have not yet occurred.

Investment Transactions and Income – Investment transactions are recorded on the trade date. Interest income is recorded on the accrual basis. All premium and discount is amortized or accreted for financial statement purposes in accordance with U.S. generally accepted accounting principles.

Fees Paid Indirectly – The fund’s custody fee may be reduced by a credit earned under an arrangement that measures the value of U.S. dollars deposited with the custodian by the fund. The amount of the credit, for the year ended August 31, 2017, is shown as a reduction of total expenses in the Statement of Operations.

Tax Matters and Distributions – The fund intends to qualify as a regulated investment company, as defined under Subchapter M of the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision for federal income tax is required. The fund’s federal tax returns, when filed, will remain subject to examination by the Internal Revenue Service for a three year period. Management has analyzed the fund’s tax positions taken on federal and state tax returns for all open tax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability.

Distributions to shareholders are recorded on the ex-dividend date. Income and capital gain distributions are determined in accordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capital accounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. These adjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certain items of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in the future. Distributions in excess of net investment income or net realized gains are temporary overdistributions for financial statement purposes resulting from differences in the recognition or classification of income or distributions for financial statement and tax purposes.

During the year ended August 31, 2017, there were no significant adjustments due to differences between book and tax accounting.

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Notes to Financial Statements – continued

The tax character of distributions declared to shareholders for the last two fiscal years is as follows:

	Year ended		Year ended
	8/31/17		8/31/16
Ordinary income (including any short-term capital gains)		$37,346,746		$12,658,614

The federal tax cost and the tax basis components of distributable earnings were as follows:

As of 8/31/17
Cost of investments	$6,273,737,471
Gross appreciation	102,533
Gross depreciation	(135,141	)
Net unrealized appreciation (depreciation)	$(32,608	)
Post-October capital loss deferral	(14,185	)

(3) Transactions with Affiliates

Investment Adviser – The fund has an investment advisory agreement with MFS to provide overall investment management and related administrative services and facilities to the fund. MFS receives no compensation under this agreement.

Shareholder Servicing Agent – MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, provides transfer agent and recordkeeping functions in connection with the issuance, transfer, and redemption of shares of the fund under a Shareholder Servicing Agent Agreement. MFSC is not paid a fee for providing these services. MFSC receives payment from the fund for out-of-pocket expenses paid by MFSC on behalf of the fund. For the year ended August 31, 2017, these costs amounted to $965. The fund may also pay shareholder servicing related costs to non-related parties.

Administrator – MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services to the fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. The fund is charged an annual fixed amount of $17,500. The administrative services fee incurred for the year ended August 31, 2017 was equivalent to an annual effective rate of 0.0003% of the fund’s average daily net assets.

Trustees’ and Officers’ Compensation – The fund may pay compensation to independent Trustees in the form of a retainer, attendance fees, and additional compensation to Board and Committee chairpersons. The fund does not pay compensation directly to Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration for their services to the fund from MFS. Certain officers and Trustees of the fund are officers or directors of MFS, MFS Fund Distributors, Inc. (MFD), and MFSC. The independent Trustees do not currently receive compensation from the fund.

Other – This fund and certain other funds managed by MFS (the funds) have entered into a service agreement (the ISO Agreement) which provides for payment of fees solely by the funds to Tarantino LLC in return for the provision of services of an Independent Senior Officer (ISO) for the funds. Frank L. Tarantino serves as the ISO and

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Notes to Financial Statements – continued

is an officer of the funds and the sole member of Tarantino LLC. The funds can terminate the ISO Agreement with Tarantino LLC at any time under the terms of the ISO Agreement. For the year ended August 31, 2017, the fee paid by the fund under this agreement was $9,403 and is included in “Miscellaneous” expense in the Statement of Operations. MFS has agreed to bear all expenses associated with office space, other administrative support, and supplies provided to the ISO.

In conjunction with the fund’s transition on August 1, 2016 from a stable net asset value to a floating net asset value, MFS made a one-time voluntary contribution (“top-up”) of $20,272 to the fund to cover the aggregate difference between the $1.00 stable net asset value per share and the new four-decimal market price per share.

(4) Shares of Beneficial Interest

The fund’s Declaration of Trust permits the Trustees to issue an unlimited number of full and fractional shares of beneficial interest. Transactions in fund shares were as follows:

	Year ended 8/31/17						Year ended 8/31/16
	Shares			Amount			Shares			Amount
Shares sold		42,815,758,008			$42,814,609,447			37,511,436,421			$37,511,436,421
Shares issued to shareholders in reinvestment of distributions		37,346,995			37,346,699			12,656,375			12,656,375
Shares reacquired		(41,201,039,211	)		(41,199,895,919	)		(38,372,263,209	)		(38,372,263,209	)
Net change		1,652,065,792			$1,652,060,227			(848,170,413	)		$(848,170,413	)

The fund is solely invested in by other MFS funds for the purpose of investing excess cash balances on a short-term basis. The MFS funds do not invest in this fund for the purpose of exercising management or control. At the end of the period, the MFS International Value Fund, the MFS Value Fund, the MFS Emerging Markets Debt Fund, and the MFS Growth Fund were the owners of record of approximately 26%, 14%, 10%, and 9%, respectively, of the value of outstanding voting shares of the fund. No other MFS fund owned more than 5% of the value of outstanding voting shares of the fund.

(5) Line of Credit

The fund and certain other funds managed by MFS participate in a $1.25 billion unsecured committed line of credit, subject to a $1 billion sublimit, provided by a syndication of banks under a credit agreement. Borrowings may be made for temporary financing needs. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the higher of the Overnight Federal Reserve funds rate or daily one month LIBOR plus an agreed upon spread. A commitment fee, based on the average daily, unused portion of the committed line of credit, is allocated among the participating funds at the end of each calendar quarter. In addition, the fund and other funds managed by MFS have established unsecured uncommitted borrowing arrangements with certain banks for temporary financing needs. Interest is charged to each fund, based on its borrowings, at a rate equal to the Overnight Federal Reserve funds rate plus an agreed upon spread. For the year ended August 31, 2017, the fund’s commitment fee and interest expense were $35,618 and $0, respectively, and the commitment fees are separately reported in the Statement of Operations.

17

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Board of Trustees of MFS Series Trust XIV and the Shareholders of MFS Institutional Money Market Portfolio:

We have audited the accompanying statement of assets and liabilities, including the portfolio of investments, of MFS Institutional Money Market Portfolio (one of the series of MFS Series Trust XIV) (the “Fund”) as of August 31, 2017, and the related statement of operations for the year then ended, the statements of changes in net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended. These financial statements and financial highlights are the responsibility of the Fund’s management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits.

We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). 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. The Fund is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, 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. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of August 31, 2017, by correspondence with the custodian and brokers. We believe that our audits provide a reasonable basis for our opinion.

In our opinion, such financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of MFS Institutional Money Market Portfolio as of August 31, 2017, 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 then ended, and the financial highlights for each of the five years in the period then ended, in conformity with accounting principles generally accepted in the United States of America.

DELOITTE & TOUCHE LLP

Boston, Massachusetts

October 17, 2017

18

RESULTS OF SHAREHOLDER MEETING

(unaudited)

On March 23, 2017, all of the shareholders of MFS Series Trust XIV voted by unanimous written consent:

Item 1: To elect the following individuals as Trustees:

Nominee

Steven E. Buller

John A. Caroselli

Maureen R. Goldfarb

David H. Gunning

Michael Hegarty

John P. Kavanaugh

Robert J. Manning

Clarence Otis, Jr.

Maryanne L. Roepke

Robin A. Stelmach

Laurie J. Thomsen

19

TRUSTEES AND OFFICERS — IDENTIFICATION AND BACKGROUND

The Trustees and Officers of the Trust, as of October 1, 2017, are listed below, together with their principal occupations during the past five years. (Their titles may have varied during that period.) The address of each Trustee and Officer is 111 Huntington Avenue, Boston, Massachusetts 02199-7618.

Name, Age	Position(s) Held with Fund	Trustee/Officer Since (h)	Number of MFS Funds overseen by the Trustee	Principal Occupations During the Past Five Years	Other Directorships During the Past Five Years (j)
INTERESTED TRUSTEES
Robert J. Manning (k) (age 53)	Trustee	February 2004	136	Massachusetts Financial Services Company, Executive Chairman (since January 2017); Director; Chairman of the Board; Chief Executive Officer (until 2015); Co-Chief Executive Officer (2015-2016)	N/A
Robin A. Stelmach (k) (age 56)	Trustee	January 2014	136	Massachusetts Financial Services Company, Vice Chair (since January 2017); Chief Operating Officer and Executive Vice President (until January 2017)	N/A
INDEPENDENT TRUSTEES
David H. Gunning (age 75)	Trustee and Chair of Trustees	January 2004	136	Private investor	Lincoln Electric Holdings, Inc., Director; Development Alternatives, Inc., Director/Non-Executive Chairman (until 2013)

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Trustees and Officers – continued

Name, Age	Position(s) Held with Fund	Trustee/Officer Since (h)	Number of MFS Funds overseen by the Trustee	Principal Occupations During the Past Five Years	Other Directorships During the Past Five Years (j)
Steven E. Buller (age 66)	Trustee	February 2014	136	Financial Accounting Standards Advisory Council, Chairman (2014-2015); Public Company Accounting Oversight Board, Standing Advisory Group, Member (until 2014); BlackRock, Inc. (investment management), Managing Director (until 2014), BlackRock Finco UK (investment management), Director (until 2014)	N/A
John A. Caroselli (age 63)	Trustee	March 2017	136	JC Global Advisors, LLC (management consulting), President (since 2015); First Capital Corporation (commercial finance), Executive Vice President (until 2015)	N/A
Maureen R. Goldfarb (age 62)	Trustee	January 2009	136	Private investor	N/A
Michael Hegarty (age 72)	Trustee	December 2004	136	Private investor	Rouse Properties Inc., Director (until 2016); Capmark Financial Group Inc., Director (until 2015)
John P. Kavanaugh (age 62)	Trustee and Vice Chair of Trustees	January 2009	136	Private investor	N/A
Clarence Otis, Jr. (age 61)	Trustee	March 2017	136	Darden Restaurants, Inc., Chief Executive Officer (until 2014)	VF Corporation, Director; Verizon Communications, Inc., Director; The Travelers Companies, Director; Federal Reserve Bank of Atlanta, Director (until 2015)

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Trustees and Officers – continued

Name, Age	Position(s) Held with Fund	Trustee/Officer Since (h)	Number of MFS Funds overseen by the Trustee	Principal Occupations During the Past Five Years	Other Directorships During the Past Five Years (j)
Maryanne L. Roepke (age 61)	Trustee	May 2014	136	American Century Investments (investment management), Senior Vice President and Chief Compliance Officer (until 2014)	N/A
Laurie J. Thomsen (age 60)	Trustee	March 2005	136	Private investor	The Travelers Companies, Director; Dycom Industries, Inc., Director (since 2015)

Name, Age	Position(s) Held with Fund	Trustee/Officer Since (h)	Number of MFS Funds for which the Person is an Officer	Principal Occupations During the Past Five Years
OFFICERS
Christopher R. Bohane (k) (age 43)	Assistant Secretary and Assistant Clerk	July 2005	136	Massachusetts Financial Services Company, Vice President and Assistant General Counsel
Kino Clark (k) (age 49)	Assistant Treasurer	January 2012	136	Massachusetts Financial Services Company, Vice President
John W. Clark, Jr. (k) (age 50)	Assistant Treasurer	April 2017	136	Massachusetts Financial Services Company, Vice President (since March 2017); Deutsche Bank (financial services), Department Head – Treasurer’s Office (until February 2017)
Thomas H. Connors (k) (age 58)	Assistant Secretary and Assistant Clerk	September 2012	136	Massachusetts Financial Services Company, Vice President and Senior Counsel; Deutsche Investment Management Americas Inc. (financial service provider), Director and Senior Counsel (until 2012)

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Trustees and Officers – continued

Name, Age	Position(s) Held with Fund	Trustee/Officer Since (h)	Number of MFS Funds for which the Person is an Officer	Principal Occupations During the Past Five Years
Ethan D. Corey (k) (age 53)	Assistant Secretary and Assistant Clerk	July 2005	136	Massachusetts Financial Services Company, Senior Vice President and Associate General Counsel
David L. DiLorenzo (k) (age 49)	President	July 2005	136	Massachusetts Financial Services Company, Senior Vice President
Heidi W. Hardin (k) (age 50)	Secretary and Clerk	April 2017	136	Massachusetts Financial Services Company, Executive Vice President and General Counsel (since March 2017); Harris Associates (investment management), General Counsel (from September 2015 to January 2017); Janus Capital Management LLC (investment management), Senior Vice President and General Counsel (until September 2015)
Brian E. Langenfeld (k) (age 44)	Assistant Secretary and Assistant Clerk	June 2006	136	Massachusetts Financial Services Company, Vice President and Senior Counsel
Susan A. Pereira (k) (age 46)	Assistant Secretary and Assistant Clerk	July 2005	136	Massachusetts Financial Services Company, Vice President and Senior Counsel
Kasey L. Phillips (k) (age 46)	Assistant Treasurer	September 2012	136	Massachusetts Financial Services Company, Vice President; Wells Fargo Funds Management, LLC, Senior Vice President, Fund Treasurer (until 2012)
Matthew A. Stowe (k) (age 42)	Assistant Secretary and Assistant Clerk	October 2014	136	Massachusetts Financial Services Company, Vice President and Assistant General Counsel
Frank L. Tarantino (age 73)	Independent Senior Officer	June 2004	136	Tarantino LLC (provider of compliance services), Principal
Richard S. Weitzel (k) (age 47)	Assistant Secretary and Assistant Clerk	October 2007	136	Massachusetts Financial Services Company, Senior Vice President and Associate General Counsel

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Trustees and Officers – continued

Name, Age	Position(s) Held with Fund	Trustee/Officer Since (h)	Number of MFS Funds for which the Person is an Officer	Principal Occupations During the Past Five Years
Martin J. Wolin (k) (age 50)	Chief Compliance Officer	July 2015	136	Massachusetts Financial Services Company, Senior Vice President and Chief Compliance Officer (since July 2015); Mercer (financial service provider), Chief Risk and Compliance Officer, North America and Latin America (until June 2015)
James O. Yost (k) (age 57)	Treasurer	September 1990	136	Massachusetts Financial Services Company, Senior Vice President

(h) Date first appointed to serve as Trustee/officer of an MFS Fund. Each Trustee has served continuously since appointment unless indicated otherwise. For the period from December 15, 2004 until February 22, 2005, Mr. Manning served as Advisory Trustee. Prior to January 2012, Messrs. DiLorenzo and Yost served as Assistant Treasurers of the Funds. From January 2012 through December 2016, Messrs. DiLorenzo and Yost served as Treasurer and Deputy Treasurer of the Funds, respectively.

(j) Directorships or trusteeships of companies required to report to the Securities and Exchange Commission (i.e., “public companies”).

(k) “Interested person” of the Trust within the meaning of the Investment Company Act of 1940 (referred to as the 1940 Act), which is the principal federal law governing investment companies like the fund, as a result of a position with MFS. The address of MFS is 111 Huntington Avenue, Boston, Massachusetts 02199-7618.

Each Trustee has been elected by shareholders and each Trustee and officer holds office until his or her successor is chosen and qualified or until his or her earlier death, resignation, retirement or removal. The Trust does not hold annual meetings for the purpose of electing Trustees, and Trustees are not elected for fixed terms. Under the terms of the Board’s retirement policy, an Independent Trustee shall retire at the end of the calendar year in which he or she reaches the earlier of 75 years of age or 15 years of service on the Board (or, in the case of any Independent Trustee who joined the Board prior to 2015, 20 years of service on the Board).

Messrs. Buller, Kavanaugh and Otis and Ms. Roepke are members of the Trust’s Audit Committee.

Each of the Interested Trustees and certain Officers hold comparable officer positions with certain affiliates of MFS.

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Trustees and Officers – continued

The Statement of Additional Information for a Fund includes further information about the Trustees and is available without charge upon request by calling 1-800-225-2606.

Investment Adviser	Custodian
Massachusetts Financial Services Company 111 Huntington Avenue Boston, MA 02199-7618	JPMorgan Chase Bank, NA 4 Metrotech Center New York, NY 11245
Distributor	Independent Registered Public Accounting Firm
MFS Fund Distributors, Inc. 111 Huntington Avenue Boston, MA 02199-7618	Deloitte & Touche LLP 200 Berkeley Street Boston, MA 02116
Portfolio Manager(s)
Edward O’Dette

25

BOARD REVIEW OF INVESTMENT ADVISORY AGREEMENT

The Investment Company Act of 1940 requires that both the full Board of Trustees and a majority of the non-interested (“independent”) Trustees, voting separately, annually approve the continuation of the Fund’s investment advisory agreement with MFS. The Trustees consider matters bearing on the Fund and its advisory arrangements at their meetings throughout the year, including a review of performance data at each regular meeting. In addition, the independent Trustees met several times over the course of three months beginning in May and ending in July, 2017 (“contract review meetings”) for the specific purpose of considering whether to approve the continuation of the investment advisory agreement for the Fund and the other investment companies that the Board oversees (the “MFS Funds”). The independent Trustees were assisted in their evaluation of the Fund’s investment advisory agreement by independent legal counsel, from whom they received separate legal advice and with whom they met separately from MFS during various contract review meetings. The independent Trustees were also assisted in this process by the MFS Funds’ Independent Senior Officer, a senior officer appointed by and reporting to the independent Trustees.

In connection with their deliberations regarding the continuation of the investment advisory agreement, the Trustees, including the independent Trustees, considered such information and factors as they believed, in light of the legal advice furnished to them and their own business judgment, to be relevant. The investment advisory agreement for the Fund was considered separately, although the Trustees also took into account the common interests of all MFS Funds in their review. As described below, the Trustees considered the nature, quality, and extent of the various investment advisory, administrative, and shareholder services performed by MFS under the existing investment advisory agreement and other arrangements with the Fund.

As part of their deliberations, the Trustees took into account that the Fund was formed solely to act as a cash sweep vehicle for other MFS Funds, and that shares of the Fund are not distributed or sold to the public. The Trustees gave substantial consideration to the fact that MFS does not charge a separate advisory fee to the Fund under the investment advisory agreement or charge transfer agency fees, administrative services fees, sales loads or distribution and service fees to the Fund, but that MFS receives advisory and other fees from the MFS Funds that invest their cash balances in the Fund.

In connection with their contract review meetings, the Trustees received and relied upon materials that included, among other items: (i) information provided by Broadridge Financial Solutions, Inc. (“Broadridge”), an independent third party, on the investment performance of the Fund for various time periods ended December 31, 2016 and the investment performance of a group of funds with substantially similar investment classifications/objectives (the “Lipper performance universe”), (ii) information provided by Broadridge on the Fund’s fees and expenses and the fees and expenses of comparable funds identified by Broadridge (the “Broadridge expense group”), (iii) information as to whether and to what extent applicable expense waivers and reimbursements are observed for the Fund, (iv) information regarding MFS’ financial results and financial condition, including MFS’ and certain of its affiliates’ estimated profitability from services performed for the Fund and the MFS Funds as a whole, and compared to MFS’ institutional business, (v) MFS’

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Board Review of Investment Advisory Agreement – continued

views regarding the outlook for the mutual fund industry and the strategic business plans of MFS, (vi) descriptions of various functions performed by MFS for the Funds, such as compliance monitoring and portfolio trading practices, and (vii) information regarding the overall organization of MFS, including information about MFS’ senior management and other personnel providing investment advisory, administrative and other services to the Fund and the other MFS Funds. The comparative performance, fee and expense information prepared and provided by Broadridge was not independently verified and the independent Trustees did not independently verify any information provided to them by MFS.

The Trustees’ conclusion as to the continuation of the investment advisory agreement was based on a comprehensive consideration of all information provided to the Trustees and not the result of any single factor. Some of the factors that figured particularly in the Trustees’ deliberations are described below, although individual Trustees may have evaluated the information presented differently from one another, giving different weights to various factors. It is also important to recognize that the fee arrangements for the Fund and other MFS Funds are the result of years of review and discussion between the independent Trustees and MFS, that certain aspects of such arrangements may receive greater scrutiny in some years than in others, and that the Trustees’ conclusions may be based, in part, on their consideration of these same arrangements during the course of the year and in prior years.

Based on information provided by Broadridge and MFS, the Trustees reviewed the Fund’s total return investment performance as well as the performance of peer groups of funds over various time periods. The Trustees placed particular emphasis on the total return performance of the Fund’s shares in comparison to the performance of funds in its Lipper performance universe over the three-year period ended December 31, 2016, which the Trustees believed was a long enough period to reflect differing market conditions. The total return performance of the Fund’s shares was in the 2nd quintile relative to the other funds in the universe for this three-year period (the 1st quintile being the best performers and the 5th quintile being the worst performers). The total return performance of the Fund’s shares was in the 2nd quintile for the one-year period and the 1st quintile for the five-year period ended December 31, 2016 relative to the Lipper performance universe. Because of the passage of time, these performance results may differ from the performance results for more recent periods, including those shown elsewhere in this report.

In the course of their deliberations, the Trustees took into account information provided by MFS in connection with the contract review meetings, as well as during investment review meetings conducted with portfolio management personnel during the course of the year regarding the Fund’s performance. After reviewing these and related factors, the Trustees concluded, within the context of their overall conclusions regarding the investment advisory agreement, that they were satisfied with MFS’ responses and efforts relating to investment performance.

In assessing the reasonableness of the Fund’s expenses, the Trustees considered, among other information, the total expense ratio of the Fund’s shares as a percentage of average daily net assets and the total expense ratios of peer groups of funds based on information provided by Broadridge, noting that the Fund’s total expense ratio was

27

Board Review of Investment Advisory Agreement – continued

expected to be relatively low because, as noted above, the Fund does not bear advisory expenses. The Trustees considered that, according to the data provided by Broadridge (which takes into account any expense limitations that were in effect during the Fund’s last fiscal year), the Fund’s total expense ratio was lower than the Broadridge expense group median. Because the Fund does not pay an advisory fee, the Trustees did not consider the extent to which economies of scale would be realized due to the Fund’s growth of assets, whether fee levels reflect economies of scale for the Fund’s shareholders, or the fees paid by similar funds to other investment advisers or by similar clients of MFS.

The Trustees also considered information prepared by MFS relating to MFS’ costs and profits with respect to the Fund, the MFS Funds considered as a group, and other investment companies and accounts advised by MFS, as well as MFS’ methodologies used to determine and allocate its costs to the MFS Funds, the Fund and other accounts and products for purposes of estimating profitability.

In addition, the Trustees considered MFS’ resources and related efforts to continue to retain, attract and motivate capable personnel to serve the Fund. The Trustees also considered current and developing conditions in the financial services industry, including the presence of large and well-capitalized companies which are spending, and appear to be prepared to continue to spend, substantial sums to engage personnel and to provide services to competing investment companies. In this regard, the Trustees also considered the financial resources of MFS and its ultimate parent, Sun Life Financial Inc. The Trustees also considered the advantages and possible disadvantages to the Fund of having an adviser that also serves other investment companies as well as other accounts.

The Trustees also considered the nature, quality, cost, and extent of administrative, transfer agency, and distribution services provided to the Fund by MFS and its affiliates under agreements and plans other than the investment advisory agreement. The Trustees also considered the nature, extent and quality of certain other services MFS performs or arranges for on the Fund’s behalf, which may include securities lending programs, directed expense payment programs, class action recovery programs, and MFS’ interaction with third-party service providers, principally custodians and sub-custodians. The Trustees concluded that the various non-advisory services provided by MFS and its affiliates on behalf of the Fund were satisfactory.

The Trustees also considered benefits to MFS from the use of the Fund’s portfolio brokerage commissions, if applicable, to pay for investment research and various other factors. Additionally, the Trustees considered so-called “fall-out benefits” to MFS such as reputational value derived from serving as investment manager to the Fund.

Based on their evaluation of factors that they deemed to be material, including those factors described above, the Board of Trustees, including the independent Trustees, concluded that the Fund’s investment advisory agreement with MFS should be continued for an additional one-year period, commencing August 1, 2017.

28

PROXY VOTING POLICIES AND INFORMATION

MFS votes proxies on behalf of the fund pursuant to proxy voting policies and procedures that are available without charge, upon request, by calling 1-800-225-2606, by visiting mfs.com (once you have selected “Individual Investor” as your role, click on “Individual Investor Home” in the top navigation and then select “Learn More About Proxy Voting” under the “I want to…” header on the left hand column of the page), or by visiting the SEC’s Web site at http://www.sec.gov.

Information regarding how the fund voted proxies relating to portfolio securities during the most recent twelve-month period ended June 30 is available by August 31 of each year without charge by visiting mfs.com (once you have selected “Individual Investor” as your role, click on “Individual Investor Home” in the top navigation and then select “Learn More About Proxy Voting” under the “I want to…” header on the left hand column of the page), or by visiting the SEC’s Web site at http://www.sec.gov.

QUARTERLY PORTFOLIO DISCLOSURE

The fund will file a complete schedule of portfolio holdings with the Securities and Exchange Commission (the Commission) for the first and third quarters of each fiscal year on Form N-Q. The fund’s Form N-Q is available on the EDGAR database on the Commission’s Internet Web site at http://www.sec.gov, and may be reviewed and copied at the:

Public Reference Room

Securities and Exchange Commission

100 F Street, NE, Room 1580

Washington, D.C. 20549

Information on the operation of the Public Reference Room may be obtained by calling the Commission at 1-800-SEC-0330. Copies of the fund’s Form N-Q also may be obtained, upon payment of a duplicating fee, by electronic request at the following e-mail address: publicinfo@sec.gov or by writing the Public Reference Section at the above address.

FURTHER INFORMATION

From time to time, MFS may post important information about the fund or the MFS funds on the MFS web site (mfs.com). This information is available on mfs.com by following these steps once you have selected “Individual Investor” as your role: Click on the “Individual Investor Home” in the top navigation and then select the “Announcements” option within the “Market Outlooks” drop down.

29

INFORMATION ABOUT FUND CONTRACTS AND LEGAL CLAIMS

The fund has entered into contractual arrangements with an investment adviser, administrator, distributor, shareholder servicing agent, 529 program manager (if applicable), and custodian who each provide services to the fund. Unless expressly stated otherwise, shareholders are not parties to, or intended beneficiaries of these contractual arrangements, and these contractual arrangements are not intended to create any shareholder right to enforce them against the service providers or to seek any remedy under them against the service providers, either directly or on behalf of the fund.

Under the Trust’s By-Laws and Declaration of Trust, any claims asserted against or on behalf of the MFS Funds, including claims against Trustees and Officers, must be brought in state and federal courts located within the Commonwealth of Massachusetts.

FEDERAL TAX INFORMATION (unaudited)

The fund will notify shareholders of amounts for use in preparing 2017 income tax forms in January 2018.

30

rev. 3/16

FACTS WHAT DOES MFS DO WITH YOUR PERSONAL INFORMATION?

Why? Financial companies choose how they share your personal information. Federal law gives consumers the right to limit some but not all sharing. Federal law also requires us to tell you how we collect, share, and protect your personal information. Please read this notice carefully to understand what we do.

What? The types of personal information we collect and share depend on the product or service you have with us. This information can include:   • Social Security number and account balances • Account transactions and transaction history • Checking account information and wire transfer instructions   When you are no longer our customer, we continue to share your information as described in this notice.

How? All financial companies need to share customers’ personal information to run their everyday business. In the section below, we list the reasons financial companies can share their customers’ personal information; the reasons MFS chooses to share; and whether you can limit this sharing.

Reasons we can share your personal information	Does MFS share?	Can you limit this sharing?
For our everyday business purposes – such as to process your transactions, maintain your account(s), respond to court orders and legal investigations, or report to credit bureaus	Yes	No
For our marketing purposes – to offer our products and services to you	No	We don’t share
For joint marketing with other financial companies	No	We don’t share
For our affiliates’ everyday business purposes – information about your transactions and experiences	No	We don’t share
For our affiliates’ everyday business purposes – information about your creditworthiness	No	We don’t share
For nonaffiliates to market to you	No	We don’t share

Questions? Call 800-225-2606 or go to mfs.com.

31

Page 2

Who we are
Who is providing this notice?	MFS Funds, MFS Investment Management, MFS Institutional Advisors, Inc., and MFS Heritage Trust Company.

What we do
How does MFS protect my personal information?	To protect your personal information from unauthorized access and use, we use security measures that comply with federal law. These measures include procedural, electronic, and physical safeguards for the protection of the personal information we collect about you.
How does MFS collect my personal information?	We collect your personal information, for example, when you • open an account or provide account information • direct us to buy securities or direct us to sell your securities • make a wire transfer We also collect your personal information from others, such as credit bureaus, affiliates, or other companies.
Why can’t I limit all sharing?	Federal law gives you the right to limit only • sharing for affiliates’ everyday business purposes – information about your creditworthiness • affiliates from using your information to market to you • sharing for nonaffiliates to market to you State laws and individual companies may give you additional rights to limit sharing.

Definitions
Affiliates	Companies related by common ownership or control. They can be financial and nonfinancial companies. • MFS does not share personal information with affiliates, except for everyday business purposes as described on page one of this notice.
Nonaffiliates	Companies not related by common ownership or control. They can be financial and nonfinancial companies. • MFS does not share with nonaffiliates so they can market to you.
Joint marketing	A formal agreement between nonaffiliated financial companies that together market financial products or services to you. • MFS doesn’t jointly market.

Other important information

If you own an MFS product or receive an MFS service in the name of a third party such as a bank or broker-dealer, their privacy policy may apply to you instead of ours.

32

Save paper with eDelivery.

MFS® will send you prospectuses,

reports, and proxies directly via e-mail so you will get information faster with less mailbox clutter.

To sign up:

1. Go to mfs.com.

2. Log in via MFS® Access.

3. Select eDelivery.

If you own your MFS fund shares through a financial institution or a retirement plan, MFS® TALK, MFS® Access, or eDelivery may not be available to you.

CONTACT

WEB SITE

mfs.com

MFS TALK

1-800-637-8255

24 hours a day

ACCOUNT SERVICE AND LITERATURE

Shareholders

1-800-225-2606

Financial advisors

1-800-343-2829

Retirement plan services

1-800-637-1255

MAILING ADDRESS

MFS Service Center, Inc.

P.O. Box 55824

Boston, MA 02205-5824

OVERNIGHT MAIL

MFS Service Center, Inc.

c/o Boston Financial Data Services

30 Dan Road

Canton, MA 02021-2809

ITEM 2. CODE OF ETHICS.

The Registrant has adopted a Code of Ethics pursuant to Section 406 of the Sarbanes-Oxley Act and as defined in Form N-CSR that applies to the Registrant’s principal executive officer and principal financial and accounting officer. Effective January 1, 2017, the Code was amended to (i) clarify that the term “for profit” company as used in Section II.B of the Code excludes the investment adviser and its subsidiaries and pooled investment vehicles sponsored by the investment adviser or its subsidiaries, (ii) align the Code’s provisions regarding receipt of gifts and entertainment in Section II.B of the Code with the gifts and entertainment policy of the Funds’ investment adviser, and (iii) make other administrative changes. During the period covered by the report, the Registrant has not granted a waiver, including an implicit waiver, from any provision of the Code.

A copy of the Code effective as of January 1, 2017 is filed as an exhibit to this Form N-CSR.

ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT.

Messrs. Steven E. Buller, John P. Kavanaugh and Clarence Otis, Jr. and Ms. Maryanne L. Roepke, members of the Audit Committee, have been determined by the Board of Trustees in their reasonable business judgment to meet the definition of “audit committee financial expert” as such term is defined in Form N-CSR. In addition, Messrs. Buller, Kavanaugh, and Otis and Ms. Roepke are “independent” members of the Audit Committee (as such term has been defined by the Securities and Exchange Commission in regulations implementing Section 407 of the Sarbanes-Oxley Act of 2002). The Securities and Exchange Commission has stated that the designation of a person as an audit committee financial expert pursuant to this Item 3 on the Form N-CSR does not impose on such a person any duties, obligations or liability that are greater than the duties, obligations or liability imposed on such person as a member of the Audit Committee and the Board of Trustees in the absence of such designation or identification

ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES.

Items 4(a) through 4(d) and 4(g):

The Board of Trustees has appointed Deloitte & Touche LLP (“Deloitte”) to serve as independent accountants to the Registrant (hereinafter the “Registrant” or the “Fund”). The tables below set forth the audit fees billed to the Fund as well as fees for non-audit services provided to the Fund and/or to the Fund’s investment adviser, Massachusetts Financial Services Company (“MFS”), and to various entities either controlling, controlled by, or under common control with MFS that provide ongoing services to the Fund (“MFS Related Entities”).

For the fiscal years ended August 31, 2017 and 2016, audit fees billed to the Fund by Deloitte were as follows:

	Audit Fees
	2017		2016
Fees Billed by Deloitte
MFS Institutional Money Market Portfolio		25,737		25,248

For the fiscal years ended August 31, 2017 and 2016, fees billed by Deloitte for audit-related, tax and other services provided to the Fund and for audit-related, tax and other services provided to MFS and MFS Related Entities were as follows:

	Audit-Related  Fees1				Tax Fees2				All Other Fees3
	2017		2016		2017		2016		2017		2016
Fees Billed by Deloitte
To MFS Institutional Money Market Portfolio		0		0		4,564		4,497		0		0
	Audit-Related Fees1				Tax Fees2				All Other Fees3
	2017		2016		2017		2016		2017		2016
Fees Billed by Deloitte
To MFS and MFS Related Entities of MFS Institutional Money Market Portfolio*		0		0		0		0		5,390		5,000

	Aggregate Fees for Non-audit Services
	2017		2016
Fees Billed by Deloitte
To MFS Institutional Money Market Portfolio, MFS and MFS Related Entities#		849,424		74,775

^*  This amount reflects the fees billed to MFS and MFS Related Entities for non-audit services relating directly to the operations and financial reporting of the Fund (portions of which services also related to the operations and financial reporting of other funds within the MFS Funds complex).

# This amount reflects the aggregate fees billed by Deloitte for non-audit services rendered to the Fund and for non-audit services rendered to MFS and the MFS Related Entities.    

¹  The fees included under “Audit-Related Fees” are fees related to assurance and related services that are reasonably related to the performance of the audit or review of financial statements, but not reported under ‘‘Audit Fees,’’ including accounting consultations, agreed-upon procedure reports, attestation reports, comfort letters and internal control reviews.

²  The fees included under “Tax Fees” are fees associated with tax compliance, tax advice and tax planning, including services relating to the filing or amendment of federal, state or local income tax returns, regulated investment company qualification reviews and tax distribution and analysis.

³  The fees included under “All Other Fees” are fees for products and services provided by Deloitte other than those reported under “Audit Fees,” “Audit-Related Fees” and “Tax Fees”.

Item 4(e)(1):

Set forth below are the policies and procedures established by the Audit Committee of the Board of Trustees relating to the pre-approval of audit and non-audit related services:

To the extent required by applicable law, pre-approval by the Audit Committee of the Board is needed for all audit and permissible non-audit services rendered to the Funds and all permissible non-audit services rendered to MFS or MFS Related Entities if the services relate directly to the operations and financial reporting of the Registrant. Pre-approval is currently on an engagement-by-engagement basis. In the event pre-approval of such services is necessary between regular meetings of the Audit Committee and it is not practical to wait to seek pre-approval at the next regular meeting of the Audit Committee, pre-approval of such services may be referred to the Chair of the Audit Committee for approval; provided that the Chair may not pre-approve any individual engagement for such services exceeding $50,000 or multiple engagements for such services in the aggregate exceeding $100,000 in each period between regular meetings of the Audit Committee. Any engagement pre-approved by the Chair between regular meetings of the Audit Committee shall be presented for ratification by the entire Audit Committee at its next regularly scheduled meeting.

Item 4(e)(2):

None, or 0%, of the services relating to the Audit-Related Fees, Tax Fees and All Other Fees paid by the Fund and MFS and MFS Related Entities relating directly to the operations and financial reporting of the Registrant disclosed above were approved by the audit committee pursuant to paragraphs (c)(7)(i)(C) of Rule 2-01 of Regulation S-X (which permits audit committee approval after the start of the engagement with respect to services other than audit, review or attest services, if certain conditions are satisfied).

Item 4(f): Not applicable.

Item 4(h): The Registrant’s Audit Committee has considered whether the provision by a Registrant’s independent registered public accounting firm of non-audit services to MFS and MFS Related Entities that were not pre-approved by the Committee (because such services did not relate directly to the operations and financial reporting of the Registrant) was compatible with maintaining the independence of the independent registered public accounting firm as the Registrant’s principal auditors.

ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS.

Not applicable to the Registrant.

ITEM 6. INVESTMENTS

A schedule of investments of the Registrant is included as part of the report to shareholders of such series under Item 1 of this Form N-CSR.

ITEM 7. DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

Not applicable to the Registrant.

ITEM 8. PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

Not applicable to the Registrant.

ITEM 9. PURCHASES OF EQUITY SECURITIES BY CLOSED-END MANAGEMENT INVESTMENT COMPANY AND AFFILIATED PURCHASERS.

Not applicable to the Registrant.    

ITEM 10. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

There were no material changes to the procedures by which shareholders may send recommendations to the Board for nominees to the Registrant’s Board since the Registrant last provided disclosure as to such procedures in response to the requirements of Item 407 (c)(2)(iv) of Regulation S-K or this Item.

ITEM 11. CONTROLS AND PROCEDURES.

(a) Based upon their evaluation of the effectiveness of the registrant’s disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940 (the “Act”)) as conducted within 90 days of the filing date of this report on Form N-CSR, the registrant’s principal financial officer and principal executive officer have concluded that those disclosure controls and procedures provide reasonable assurance that the material information required to be disclosed by the registrant on this report is recorded, processed, summarized and reported within the time periods specified in the Securities and Exchange Commission’s rules and forms.

(b) There were no changes in the registrant’s internal controls over financial reporting (as defined in Rule 30a-3(d) under the Act) that occurred during the second fiscal quarter of the period covered by the report that have materially affected, or are reasonably likely to materially affect, the registrant’s internal control over financial reporting.

ITEM 12. DISCLOSURE OF SECURITIES LENDING ACTIVITIES FOR CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

Not applicable to the Registrant.

ITEM 13. EXHIBITS.

(a) File the exhibits listed below as part of this form. Letter or number the exhibits in the sequence indicated.

(1) Any code of ethics, or amendment thereto, that is the subject of the disclosure required by Item 2, to the extent that the registrant intends to satisfy the Item 2 requirements through filing of an exhibit: Code of Ethics attached hereto.

(2) A separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2 under the Act (17 CFR 270.30a-2): Attached hereto.

(b) If the report is filed under Section 13(a) or 15(d) of the Exchange Act, provide the certifications required by Rule 30a-2(b) under the Act (17 CFR 270.30a-2(b)), Rule 13a-14(b) or Rule 15d-14(b) under the Exchange Act (17 CFR 240.13a-14(b) or 240.15d-14(b)) and Section 1350 of Chapter 63 of Title 18 of the United States Code (18 U.S.C. 1350) as an exhibit. A certification furnished pursuant to this paragraph will not be deemed “filed” for the purposes of Section 18 of the Exchange Act (15 U.S.C. 78r), or otherwise subject to the liability of that section. Such certification will not be deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Exchange Act, except to the extent that the registrant specifically incorporates it by reference: Attached hereto.

Notice

A copy of the Declaration of Trust, as amended, of the Registrant is on file with the Secretary of State of The Commonwealth of Massachusetts and notice is hereby given that this instrument is executed on behalf of the Registrant by an officer of the Registrant as an officer and not individually and the obligations of or arising out of this instrument are not binding upon any of the Trustees or shareholders individually, but are binding only upon the assets and property of the respective constituent series of the Registrant.

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.

(Registrant) MFS SERIES TRUST XIV

By (Signature and Title)*	DAVID L. DILORENZO
	David L. DiLorenzo, President

Date: October 17, 2017

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 (Signature and Title)*	DAVID L. DILORENZO
	David L. DiLorenzo, President (Principal Executive Officer)

Date: October 17, 2017

By (Signature and Title)*	JAMES O. YOST
	James O. Yost, Treasurer (Principal Financial Officer and Accounting Officer)

Date: October 17, 2017

* Print name and title of each signing officer under his or her signature.

EX-99.(12)(A)(1)

EX-99.COE

Code of Ethics for Principal Executive and Principal Financial Officers

Effective January 1, 2017

I. Policy Purpose and Summary

Section 406 of the Sarbanes-Oxley Act requires that the each MFS Fund registered under the Investment Company Act of 1940 adopt a code of ethics for senior financial officers, applicable to its principal financial officer and principal accounting officer.

II. Overview

A. Covered Officers/Purpose of the Code

This code of ethics (this “Code”) has been adopted by the funds (collectively, “Funds” and each, “Fund”) under supervision of the MFS Funds Board (the “Board”) and applies to the Funds’ Principal Executive Officer and Principal Financial Officer (the “Covered Officers” each of whom is set forth in Exhibit A) for the purpose of promoting:

• honest and ethical conduct, including the ethical handling of actual or apparent conflicts of interest between personal and professional relationships;

• full, fair, accurate, timely and understandable disclosure in reports and documents that the Funds file with, or submit to, the Securities and Exchange Commission (“SEC”) and in other public communications made by the Funds;

• compliance by the Funds with applicable laws and governmental rules and regulations;

• the prompt internal reporting of violations of the Code to an appropriate person or persons identified in the Code; and

• accountability for adherence to the Code.

B. Conduct Guidelines

Each Covered Officer should adhere to a high standard of business ethics and should be sensitive to situations that may give rise to actual as well as apparent conflicts of interest. In addition, each Covered Officer should not place his or her personal interests ahead of the Funds’ interests and should endeavor to act honestly and ethically. In furtherance of the foregoing, each Covered Officer must:

• not use his or her personal influence or personal relationships improperly to influence investment decisions or financial reporting for any Fund whereby the Covered Officer would benefit personally to the detriment of the Fund; and

• not cause a Fund to take action, or fail to take action, for the individual personal benefit of the Covered Officer rather than the benefit the Fund.

The following activities, which could create the appearance of a conflict of interest, are permitted only with the approval of the Funds’ Chief Legal Officer (“CLO”):

• service as a director on the board of any “for profit” company other than the board of the Funds’ investment adviser or its subsidiaries or board of a pooled investment vehicle sponsored by the Funds’ investment adviser or its subsidiaries;

• running for political office;

• the receipt of any Fund business-related gift or any entertainment from any company with which a Fund has current or prospective business dealings unless such gift or entertainment is permitted by the gifts and entertainment policy of the Funds’ investment adviser;

• any material ownership interest in, or any consulting or employment relationship with, any Fund service providers (e.g., custodian banks, audit firms), other than the Funds’ investment adviser, principal underwriter, administrator or any affiliated person thereof;

• a direct or indirect financial interest in commissions, transaction charges or spreads paid by a Fund for effecting portfolio transactions or for selling or redeeming shares, other than an interest arising from the Covered Officer’s employment or securities ownership.

C. Disclosure and Compliance

• Each Covered Officer should familiarize himself or herself with the disclosure requirements generally applicable to the Funds;

• each Covered Officer should not knowingly misrepresent, or cause others to misrepresent, facts about a Fund to others, whether within or outside the Fund, including to the Fund’s trustees and auditors, and to governmental regulators and self-regulatory organizations;

• each Covered Officer should, to the extent appropriate within his or her area of Fund responsibility, consult with other officers and employees of the Funds and the adviser with the goal of promoting full, fair, accurate, timely and understandable disclosure in the reports and documents the Funds file with, or submit to, the SEC and in other public communications made by the Funds; and

• it is the responsibility of each Covered Officer to promote compliance within his or her area of Fund responsibility with the standards and restrictions imposed by applicable laws, rules and regulations.

D. Reporting and Accountability

Each Covered Officer must:

• upon adoption of the Code (or thereafter as applicable, upon becoming a Covered Officer), affirm in writing to the Boards that he or she has received, read, and understands the Code;

• annually thereafter affirm to the Boards that he or she has complied with the requirements of the Code;

• annually report to the CLO affiliations and relationships which are or may raise the appearance of a conflict of interest with the Covered Officer’s duties to the Funds, as identified in the annual Trustee and Officer Questionnaire;

• not retaliate against any other Covered Officer or any officer or employee of the Funds or their affiliated persons for reports of potential violations that are made in good faith; and

• notify the CLO promptly if he or she knows of any violation of this Code. Failure to do so is itself a violation of this Code.

The CLO is responsible for applying this Code to specific situations in which questions are presented under it, granting waivers upon consultation with the appropriate Board or its designee, investigating violations, and has the authority to interpret this Code in any particular situation. The CLO will report requests for waivers to the appropriate Board (or a designee thereof) promptly upon receipt of a waiver request and will periodically report to the appropriate Board any approvals granted since the last report.

The CLO will take all appropriate action to investigate any potential violations reported to him or her and to report any violations to the appropriate Board. If the Board concurs that a violation has occurred, it will consider appropriate action, which may include review of, and appropriate modifications to, applicable policies and procedures; notification to appropriate personnel of the investment adviser or its board; or a recommendation to dismiss the Covered Officer.

Any changes to or waivers of this Code will, to the extent required, be disclosed as provided by SEC rules.

E. Confidentiality

All reports and records prepared or maintained pursuant to this Code and under the direction of the CLO will be considered confidential and shall be maintained and protected accordingly. Except as otherwise required by law or this Code, such matters shall not be disclosed to anyone other than the appropriate Funds’ Board, its counsel, counsel to the Board’s independent trustees and senior management and the board of directors of the Fund’s investment adviser and its counsel.

F. Internal Use

The Code is intended solely for the internal use by the Funds and does not constitute an admission, by or on behalf of any Fund, as to any fact, circumstance, or legal conclusion.

III. Supervision

The Board of Trustees of the Fund, including a majority of the Trustees who are not “interested persons” (as defined in the 1940 Act) of the Fund, shall review no less frequently than annually, a report from the CLO regarding the affirmations of the principal executive officer and the principal financial officer as to compliance with this Code.

IV. Interpretation and Escalation

Breaches of the Code are reviewed by the CLO and communicated to the Board of Trustees of the affected Fund(s). Interpretations of this Policy shall be made from time to time by the CLO, as needed, and questions regarding the application of this Policy to a specific set of facts are escalated to the CLO.

V. Authority

Section 406 of the Sarbanes-Oxley Act.

VI. Monitoring

Adherence to this policy is monitored by the CLO.

VII. Related Policies

This Code shall be the sole code of ethics adopted by the Funds for purposes of Section 406 of the Sarbanes-Oxley Act and the rules and forms applicable to registered investment companies thereunder. Insofar as other policies or procedures of the Funds, the Funds’ adviser, principal underwriter, or other service providers govern or purport to govern the behavior or activities of the Covered Officers who are subject to this Code, they are superseded by this Code to the extent that they overlap or conflict with the provisions of this Code. The Funds’ and their investment adviser’s codes of ethics under Rule 17j-1 under the Investment Company Act and any other codes or policies or procedures adopted by the Funds or their investment adviser or other service providers are separate requirements and are not part of this Code.

VIII. Amendment

Any amendments to this Code, other than amendments to Exhibit A, must be approved or ratified by a majority vote of each Board, including a majority of independent trustees.

IX. Recordkeeping

All required books, records and other documentation shall be retained in accordance with MFS’ related record retention policy.

Additional procedures may need to be implemented by departments to properly comply with this policy.

Exhibit A

As of January 1, 2017

Persons Covered by this Code of Ethics

Funds’ Principal Executive Officer: David L. DiLorenzo

Funds’ Principal Financial Officer: James O. Yost

EX-99.CERT

EX-99.302CERT

MFS SERIES TRUST XIV

CERTIFICATION PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT

I, James O. Yost, certify that:

1. I have reviewed this report on Form N-CSR of MFS Series Trust XIV;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

a. Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b. Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c. Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures as of a date within 90 days prior to the filing date of this report based on such evaluation; and

d. Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the second fiscal quarter of the period covered by the report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a. All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize, and report financial information; and

b. Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: October 17, 2017	JAMES O. YOST
	James O. Yost Treasurer (Principal Financial Officer and Accounting Officer)

EX-99.302CERT

MFS SERIES TRUST XIV

CERTIFICATION PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT

I, David L. DiLorenzo, certify that:

1. I have reviewed this report on Form N-CSR of MFS Series Trust XIV;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3. Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4. The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

a. Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b. Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c. Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures as of a date within 90 days prior to the filing date of this report based on such evaluation; and

d. Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the second fiscal quarter of the period covered by the report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5. The registrant’s other certifying officer and I have disclosed to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

a. All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize, and report financial information; and

b. Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date: October 17, 2017	DAVID L. DILORENZO
	David L. DiLorenzo President (Principal Executive Officer)

EX-99.906CERT

EX-99.906CERT

MFS SERIES TRUST XIV

CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT

I, James O. Yost, certify that, to my knowledge:

1. The Form N-CSR (the “Report”) of MFS Series Trust XIV (the “Registrant”) fully complies for the period covered by the Report with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date: October 17, 2017	JAMES O. YOST
	James O. Yost Treasurer (Principal Financial Officer and Accounting Officer)

A signed original of this written statement required by Section 906 has been provided to the Registrant and will be retained by the Registrant and furnished to the Securities and Exchange Commission or its staff upon request.

EX-99.906CERT

MFS SERIES TRUST XIV

CERTIFICATION PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT

I, David L. DiLorenzo, certify that, to my knowledge:

1. The Form N-CSR (the “Report”) of MFS Series Trust XIV (the “Registrant”) fully complies for the period covered by the Report with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date: October 17, 2017	DAVID L. DILORENZO
	David L. DiLorenzo President (Principal Executive Officer)

A signed original of this written statement required by Section 906 has been provided to the Registrant and will be retained by the Registrant and furnished to the Securities and Exchange Commission or its staff upon request.