N-CSRS

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 811-00859

MASSACHUSETTS INVESTORS GROWTH STOCK FUND

(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: November 30

Date of reporting period: May 31, 2021

ITEM 1. REPORTS TO STOCKHOLDERS.

Item 1(a):

Semiannual Report

May 31, 2021

Massachusetts Investors
Growth Stock Fund

MIG-SEM

Massachusetts Investors
Growth Stock Fund

CONTENTS

Letter from the CEO	1
Portfolio composition	2
Expense table	3
Portfolio of investments	6
Statement of assets and liabilities	10
Statement of operations	12
Statements of changes in net assets	13
Financial highlights	14
Notes to financial statements	26
Statement regarding liquidity risk management program	37
Proxy voting policies and information	38
Quarterly portfolio disclosure	38
Further information	38
Information about fund contracts and legal claims	38
Provision of financial reports and summary prospectuses	38

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 CEO

Dear Shareholders:

Markets have experienced dramatic swings since the coronavirus pandemic brought the global economy to a standstill for several months early in 2020. While the speedy development of vaccines brightened the economic and market outlook, uncertainty remains as new variants of the virus appear, and questions persist over how fast vaccines can be made widely available in the developing world.

Global central banks have taken aggressive steps to cushion the economic and market fallout related to the virus, and governments are deploying unprecedented levels of fiscal support. Having passed a $1.9 trillion stimulus package in March, the U.S. Congress could approve additional stimulus later this year, some of it focused on infrastructure. Along with extraordinary government expenditures, pent-up consumer demand fueled a surge in economic activity as coronavirus restrictions were eased, pushing up inflation, at least temporarily. Markets reacted by pushing up yields on global government bonds, though some of the rate rise has since been corrected.

A spirited debate is underway among investors over whether the current price pressures will persist or prove to be temporary, caused by pandemic-induced bottlenecks. The policy measures put in place to counteract the pandemic's effects have helped build a supportive environment and are encouraging economic recovery; however, if markets disconnect from fundamentals, they can sow the seeds of instability. As such, recent dramatic increases in speculative trading in cryptocurrencies, special purpose acquisition companies (SPACs), and the like bear watching.

In the aftermath of the crisis, we could see societal changes as households, businesses, and governments adjust to a new reality, and any such alterations could affect the investment landscape. For investors, events such as the COVID-19 outbreak demonstrate the importance of having a deep understanding of company fundamentals, and we have built our global research platform to do just that.

At MFS^®, we put our clients’ assets to work responsibly by carefully navigating the increasing complexity of global markets and economies. Guided by our long-term philosophy and adhering to our commitment to sustainable investing, we tune out the noise and aim to uncover what we believe are the best, most durable investment opportunities in the market. Our unique global investment platform combines collective expertise, long-term discipline, and thoughtful risk management to create sustainable value for investors.

Respectfully,

Michael W. Roberge

Chief Executive Officer

MFS Investment Management

July 16, 2021

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

Top ten holdings

Microsoft Corp.	10.1%
Alphabet, Inc., “A”	8.3%
Apple, Inc.	4.2%
Accenture PLC, “A”	3.7%
Visa, Inc., “A”	3.0%
Aon PLC	2.8%
Colgate-Palmolive Co.	2.7%
Fiserv, Inc.	2.5%
Boston Scientific Corp.	2.4%
Charles Schwab Corp.	2.1%

GICS equity sectors (g)

Information Technology	33.6%
Health Care	15.8%
Communication Services	12.7%
Consumer Discretionary	11.7%
Financials	8.2%
Consumer Staples	7.2%
Industrials	6.1%
Real Estate	2.0%
Materials	1.5%
Utilities	0.7%

 

(g) The Global Industry Classification Standard (GICS^®) was developed by and/or is the exclusive property of MSCI, Inc. and S&P Global Market Intelligence Inc. (“S&P Global Market Intelligence”). GICS is a service mark of MSCI and S&P Global Market Intelligence and has been licensed for use by MFS. MFS has applied its own internal sector/industry classification methodology for equity securities and non-equity securities that are unclassified by GICS.

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. Please see the Statement of Assets and Liabilities for additional information related to the fund’s cash position and other assets and liabilities.

Percentages are based on net assets as of May 31, 2021.

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

2

Expense Table

Fund expenses borne by the shareholders during the period,
December 1, 2020 through May 31, 2021

As a shareholder of the fund, you incur two types of costs: (1) transaction costs, including sales charges (loads) on certain purchase or redemption payments, and (2) ongoing costs, including management fees; distribution and service (12b-1) fees; and other fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in the fund and to compare these costs with the ongoing costs of investing in other mutual funds.

The example is based on an investment of $1,000 invested at the beginning of the period and held for the entire period December 1, 2020 through May 31, 2021.

Actual Expenses

The first line for each share class in 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 for each share class in 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 for each share class in 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.

3

Expense Table - continued

Share Class		Annualized Expense Ratio	Beginning Account Value 12/01/20	Ending Account Value 5/31/21	Expenses Paid During Period (p) 12/01/20-5/31/21
A	Actual	0.70%	$1,000.00	$1,142.71	$3.74
	Hypothetical (h)	0.70%	$1,000.00	$1,021.44	$3.53
B	Actual	1.45%	$1,000.00	$1,138.29	$7.73
	Hypothetical (h)	1.45%	$1,000.00	$1,017.70	$7.29
C	Actual	1.45%	$1,000.00	$1,138.43	$7.73
	Hypothetical (h)	1.45%	$1,000.00	$1,017.70	$7.29
I	Actual	0.45%	$1,000.00	$1,144.19	$2.41
	Hypothetical (h)	0.45%	$1,000.00	$1,022.69	$2.27
R1	Actual	1.45%	$1,000.00	$1,138.51	$7.73
	Hypothetical (h)	1.45%	$1,000.00	$1,017.70	$7.29
R2	Actual	0.95%	$1,000.00	$1,141.23	$5.07
	Hypothetical (h)	0.95%	$1,000.00	$1,020.19	$4.78
R3	Actual	0.70%	$1,000.00	$1,142.60	$3.74
	Hypothetical (h)	0.70%	$1,000.00	$1,021.44	$3.53
R4	Actual	0.45%	$1,000.00	$1,143.94	$2.41
	Hypothetical (h)	0.45%	$1,000.00	$1,022.69	$2.27
R6	Actual	0.36%	$1,000.00	$1,144.70	$1.92
	Hypothetical (h)	0.36%	$1,000.00	$1,023.14	$1.82
529A	Actual	0.74%	$1,000.00	$1,142.49	$3.95
	Hypothetical (h)	0.74%	$1,000.00	$1,021.24	$3.73
529B	Actual	0.75%	$1,000.00	$1,142.49	$4.01
	Hypothetical (h)	0.75%	$1,000.00	$1,021.19	$3.78
529C	Actual	1.50%	$1,000.00	$1,138.32	$8.00
	Hypothetical (h)	1.50%	$1,000.00	$1,017.45	$7.54

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

(p) “Expenses Paid During Period” are equal to each class’s annualized expense ratio, as shown above, multiplied by the average account value over the period, multiplied by 182/365 (to reflect the one-half year period). Expenses paid do not include any applicable sales charges (loads). If these transaction costs had been included, your costs would have been higher.

Notes to Expense Table

For the period from December 1, 2020 through May 31, 2021, the distribution fee for Class 529B was not imposed. Had the distribution fee been imposed throughout the entire six month period, the annualized expense ratio, the actual expenses paid during the period, and the hypothetical expenses paid during the period would have been approximately 1.50%, $8.01, and $7.54 for Class 529B. See Note 3 in the Notes to Financial Statements for additional information.

Each class with a Rule 12b-1 service fee is subject to a rebate of a portion of such fee. Such rebates are included in the expense ratios above. For Class 529A shares, this rebate reduced the

4

Expense Table - continued

expense ratio above by 0.02%. See Note 3 in the Notes to Financial Statements for additional information.

5

Portfolio of Investments

5/31/21 (unaudited)

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

Issuer	Shares/Par	Value ($)
Common Stocks – 99.5%
Apparel Manufacturers – 4.5%
Adidas AG	401,339	$    146,423,437
LVMH Moet Hennessy Louis Vuitton SE	168,912	134,673,235
NIKE, Inc., “B”	1,394,733	190,325,265
		$471,421,937
Brokerage & Asset Managers – 2.9%
Blackstone Group, Inc.	847,315	$     78,520,681
Charles Schwab Corp.	3,053,425	225,495,436
		$304,016,117
Business Services – 10.7%
Accenture PLC, “A”	1,383,081	$    390,250,135
Cognizant Technology Solutions Corp., “A”	1,047,193	74,937,131
Equifax, Inc.	600,398	141,117,546
Fidelity National Information Services, Inc.	1,089,777	162,354,977
Fiserv, Inc. (a)	2,241,443	258,214,234
Verisk Analytics, Inc., “A”	574,516	99,293,600
		$1,126,167,623
Cable TV – 1.2%
Charter Communications, Inc., “A” (a)	181,576	$    126,109,979
Computer Software – 10.1%
Microsoft Corp.	4,247,665	$  1,060,556,997
Computer Software - Systems – 4.2%
Apple, Inc.	3,583,048	$    446,483,611
Construction – 2.7%
Otis Worldwide Corp.	1,601,234	$    125,424,659
Sherwin-Williams Co.	547,983	155,369,620
		$280,794,279
Consumer Products – 5.5%
Church & Dwight Co., Inc.	1,653,875	$    141,786,704
Colgate-Palmolive Co.	3,351,494	280,788,168
Estee Lauder Cos., Inc., “A”	490,116	150,230,356
		$572,805,228

6

Portfolio of Investments (unaudited) – continued

Issuer	Shares/Par	Value ($)
Common Stocks – continued
Electrical Equipment – 4.8%
Amphenol Corp., “A”	3,229,851	$    217,239,778
Fortive Corp.	1,817,265	131,788,058
TE Connectivity Ltd.	1,162,290	157,699,507
		$506,727,343
Electronics – 3.1%
Analog Devices, Inc.	711,713	$    117,147,960
Taiwan Semiconductor Manufacturing Co. Ltd., ADR	722,700	84,816,072
Texas Instruments, Inc.	651,041	123,580,603
		$325,544,635
Food & Beverages – 1.7%
PepsiCo, Inc.	1,226,444	$    181,440,126
General Merchandise – 1.7%
Dollarama, Inc.	4,161,271	$    180,999,774
Health Maintenance Organizations – 1.0%
Cigna Corp.	419,801	$    108,665,489
Insurance – 4.3%
Aon PLC	1,145,443	$    290,220,893
Marsh & McLennan Cos., Inc.	1,156,243	159,966,219
		$450,187,112
Internet – 11.3%
Alibaba Group Holding Ltd. (a)	7,579,512	$    206,053,898
Alphabet, Inc., “A” (a)	371,961	876,656,283
Tencent Holdings Ltd.	1,338,600	106,757,552
		$1,189,467,733
Leisure & Toys – 2.1%
Electronic Arts, Inc.	1,561,144	$    223,134,312
Medical & Health Technology & Services – 1.6%
ICON PLC (a)	339,924	$     76,061,394
PRA Health Sciences, Inc. (a)	532,111	90,948,412
		$167,009,806
Medical Equipment – 12.9%
Abbott Laboratories	907,001	$    105,801,667
Agilent Technologies, Inc.	868,867	120,016,599
Becton, Dickinson and Co.	736,175	178,073,371
Boston Scientific Corp. (a)	6,034,336	256,760,997
Danaher Corp.	615,652	157,693,103
Medtronic PLC	826,244	104,594,228

7

Portfolio of Investments (unaudited) – continued

Issuer	Shares/Par	Value ($)
Common Stocks – continued
Medical Equipment – continued
STERIS PLC	570,760	$    108,935,253
Stryker Corp.	768,955	196,291,143
Thermo Fisher Scientific, Inc.	264,583	124,221,718
		$1,352,388,079
Other Banks & Diversified Financials – 5.2%
Mastercard, Inc., “A”	349,615	$    126,064,177
Moody's Corp.	318,924	106,951,163
Visa, Inc., “A”	1,386,362	315,120,083
		$548,135,423
Pharmaceuticals – 0.4%
Roche Holding AG	105,706	$     36,773,952
Railroad & Shipping – 1.3%
Union Pacific Corp.	627,982	$    141,126,395
Restaurants – 1.4%
Starbucks Corp.	1,293,575	$    147,312,321
Specialty Stores – 2.2%
Ross Stores, Inc.	939,374	$    118,727,480
TJX Cos., Inc.	1,651,735	111,558,182
		$230,285,662
Telecommunications - Wireless – 2.0%
American Tower Corp., REIT	819,494	$    209,347,937
Utilities - Electric Power – 0.7%
Xcel Energy, Inc.	1,018,534	$     72,193,690
Total Common Stocks (Identified Cost, $5,102,428,108)		$10,459,095,560
Investment Companies (h) – 0.2%
Money Market Funds – 0.2%
MFS Institutional Money Market Portfolio, 0.03% (v) (Identified Cost, $19,595,278)	19,595,279	$     19,595,279
Other Assets, Less Liabilities – 0.3%		28,808,224
Net Assets – 100.0%		$10,507,499,063

(a)	Non-income producing security.
(h)	An affiliated issuer, which may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. At period end, the aggregate values of the fund's investments in affiliated issuers and in unaffiliated issuers were $19,595,279 and $10,459,095,560, respectively.

8

Portfolio of Investments (unaudited) – continued

(v) Affiliated issuer that is available only to investment companies managed by MFS. The rate quoted for the MFS Institutional Money Market Portfolio is the annualized seven-day yield of the fund at period end.

The following abbreviations are used in this report and are defined:
ADR	American Depositary Receipt
REIT	Real Estate Investment Trust

See Notes to Financial Statements

9

Financial Statements

Statement of Assets and Liabilities

At 5/31/21 (unaudited)

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, $5,102,428,108)	$10,459,095,560
Investments in affiliated issuers, at value (identified cost, $19,595,278)	19,595,279
Receivables for
Fund shares sold	31,910,226
Dividends	10,611,483
Other assets	127,728
Total assets	$10,521,340,276
Liabilities
Payables for
Fund shares reacquired	$10,424,286
Payable to affiliates
Investment adviser	473,600
Administrative services fee	7,722
Shareholder servicing costs	2,337,402
Distribution and service fees	216,955
Program manager fees	406
Payable for independent Trustees' compensation	6,380
Accrued expenses and other liabilities	374,462
Total liabilities	$13,841,213
Net assets	$10,507,499,063
Net assets consist of
Paid-in capital	$4,395,898,934
Total distributable earnings (loss)	6,111,600,129
Net assets	$10,507,499,063
Shares of beneficial interest outstanding	252,437,268

10

Statement of Assets and Liabilities (unaudited) – continued

	Net assets	Shares outstanding	Net asset value per share (a)
Class A	$5,016,253,940	121,551,668	$41.27
Class B	34,430,542	1,013,070	33.99
Class C	73,798,632	2,189,651	33.70
Class I	1,164,429,825	27,239,318	42.75
Class R1	34,098,273	1,029,948	33.11
Class R2	103,262,761	2,592,880	39.83
Class R3	644,357,638	15,825,215	40.72
Class R4	922,482,155	22,147,316	41.65
Class R6	2,455,089,384	57,338,955	42.82
Class 529A	52,312,488	1,293,136	40.45
Class 529B	669,452	20,284	33.00
Class 529C	6,313,973	195,827	32.24

(a) Maximum offering price per share was equal to the net asset value per share for all share classes, except for Classes A and 529A, for which the maximum offering prices per share were $43.79 [100 / 94.25 x $41.27] and $42.92 [100 / 94.25 x $40.45], respectively. On sales of $50,000 or more, the maximum offering prices of Class A and Class 529A shares are reduced. A contingent deferred sales charge may be imposed on redemptions of Class A, Class B, Class C, Class 529B, and Class 529C shares. Redemption price per share was equal to the net asset value per share for Classes I, R1, R2, R3, R4, R6, and 529A.

See Notes to Financial Statements

11

Financial Statements

Statement of Operations

Six months ended 5/31/21 (unaudited)

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)
Income
Dividends	$52,029,520
Other	144,680
Dividends from affiliated issuers	15,919
Foreign taxes withheld	(833,030)
Total investment income	$51,357,089
Expenses
Management fee	$16,647,327
Distribution and service fees	7,823,512
Shareholder servicing costs	4,264,668
Program manager fees	13,689
Administrative services fee	271,826
Independent Trustees' compensation	48,888
Custodian fee	186,176
Shareholder communications	136,744
Audit and tax fees	55,829
Legal fees	32,261
Miscellaneous	170,860
Total expenses	$29,651,780
Reduction of expenses by distributor	(31,114)
Net expenses	$29,620,666
Net investment income (loss)	$21,736,423
Realized and unrealized gain (loss)
Realized gain (loss) (identified cost basis)
Unaffiliated issuers	$579,858,869
Foreign currency	81,422
Net realized gain (loss)	$579,940,291
Change in unrealized appreciation or depreciation
Unaffiliated issuers	$755,878,343
Translation of assets and liabilities in foreign currencies	43,824
Net unrealized gain (loss)	$755,922,167
Net realized and unrealized gain (loss)	$1,335,862,458
Change in net assets from operations	$1,357,598,881

See Notes to Financial Statements

12

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.

	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20
Change in net assets
From operations
Net investment income (loss)	$21,736,423	$40,883,324
Net realized gain (loss)	579,940,291	899,092,818
Net unrealized gain (loss)	755,922,167	842,384,106
Change in net assets from operations	$1,357,598,881	$1,782,360,248
Total distributions to shareholders	$(700,003,350)	$(572,891,923)
Change in net assets from fund share transactions	$128,350,710	$243,031,861
Total change in net assets	$785,946,241	$1,452,500,186
Net assets
At beginning of period	9,721,552,822	8,269,052,636
At end of period	$10,507,499,063	$9,721,552,822

See Notes to Financial Statements

13

Financial Statements

Financial Highlights

The financial highlights table is intended to help you understand the fund's financial performance for the semiannual period and the past 5 fiscal 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.

Class A	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$38.83	$34.13	$30.34	$29.26	$24.25	$25.16
Income (loss) from investment operations
Net investment income (loss) (d)	$0.06	$0.13	$0.19	$0.22	$0.21	$0.18(c)
Net realized and unrealized gain (loss)	5.17	6.92	6.41	2.77	6.16	0.41
Total from investment operations	$5.23	$7.05	$6.60	$2.99	$6.37	$0.59
Less distributions declared to shareholders
From net investment income	$(0.06)	$(0.09)	$(0.27)	$(0.25)	$(0.18)	$(0.21)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.79)	$(2.35)	$(2.81)	$(1.91)	$(1.36)	$(1.50)
Net asset value, end of period (x)	$41.27	$38.83	$34.13	$30.34	$29.26	$24.25
Total return (%) (r)(s)(t)(x)	14.33(n)	21.97	24.88	10.79	27.71	2.66(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	0.70(a)	0.71	0.72	0.72	0.74	0.74(c)
Expenses after expense reductions (f)	0.70(a)	0.70	0.70	0.70	0.72	0.73(c)
Net investment income (loss)	0.32(a)	0.38	0.62	0.75	0.79	0.76(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$5,016,254	$4,577,864	$4,439,886	$3,820,208	$3,672,640	$3,276,518

See Notes to Financial Statements

14

Financial Highlights – continued

Class B	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$32.52	$29.07	$26.24	$25.54	$21.33	$22.28
Income (loss) from investment operations
Net investment income (loss) (d)	$(0.07)	$(0.10)	$(0.04)	$(0.00)(w)	$0.01	$(0.00)(c)(w)
Net realized and unrealized gain (loss)	4.27	5.81	5.47	2.41	5.39	0.38
Total from investment operations	$4.20	$5.71	$5.43	$2.41	$5.40	$0.38
Less distributions declared to shareholders
From net investment income	$—	$—	$(0.06)	$(0.05)	$(0.01)	$(0.04)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.73)	$(2.26)	$(2.60)	$(1.71)	$(1.19)	$(1.33)
Net asset value, end of period (x)	$33.99	$32.52	$29.07	$26.24	$25.54	$21.33
Total return (%) (r)(s)(t)(x)	13.90(n)	21.07	23.93	9.98	26.67	1.96(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	1.45(a)	1.46	1.47	1.47	1.49	1.49(c)
Expenses after expense reductions (f)	1.45(a)	1.45	1.46	1.46	1.48	1.49(c)
Net investment income (loss)	(0.44)(a)	(0.37)	(0.14)	(0.02)	0.04	(0.01)(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$34,431	$37,539	$45,867	$49,446	$58,530	$62,185

See Notes to Financial Statements

15

Financial Highlights – continued

Class C	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$32.27	$28.86	$26.01	$25.34	$21.19	$22.16
Income (loss) from investment operations
Net investment income (loss) (d)	$(0.07)	$(0.11)	$(0.04)	$(0.01)	$0.01	$(0.00)(c)(w)
Net realized and unrealized gain (loss)	4.23	5.78	5.43	2.40	5.35	0.37
Total from investment operations	$4.16	$5.67	$5.39	$2.39	$5.36	$0.37
Less distributions declared to shareholders
From net investment income	$—	$—	$—	$(0.06)	$(0.03)	$(0.05)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.73)	$(2.26)	$(2.54)	$(1.72)	$(1.21)	$(1.34)
Net asset value, end of period (x)	$33.70	$32.27	$28.86	$26.01	$25.34	$21.19
Total return (%) (r)(s)(t)(x)	13.88(n)	21.08	23.90	9.97	26.66	1.94(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	1.45(a)	1.46	1.47	1.47	1.49	1.49(c)
Expenses after expense reductions (f)	1.45(a)	1.46	1.47	1.47	1.49	1.49(c)
Net investment income (loss)	(0.44)(a)	(0.38)	(0.15)	(0.04)	0.04	(0.01)(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$73,799	$83,412	$88,997	$87,033	$223,841	$233,753

See Notes to Financial Statements

16

Financial Highlights – continued

Class I	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$40.17	$35.22	$31.23	$30.03	$24.87	$25.76
Income (loss) from investment operations
Net investment income (loss) (d)	$0.11	$0.21	$0.27	$0.30	$0.27	$0.24(c)
Net realized and unrealized gain (loss)	5.35	7.16	6.60	2.85	6.32	0.43
Total from investment operations	$5.46	$7.37	$6.87	$3.15	$6.59	$0.67
Less distributions declared to shareholders
From net investment income	$(0.15)	$(0.16)	$(0.34)	$(0.29)	$(0.25)	$(0.27)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.88)	$(2.42)	$(2.88)	$(1.95)	$(1.43)	$(1.56)
Net asset value, end of period (x)	$42.75	$40.17	$35.22	$31.23	$30.03	$24.87
Total return (%) (r)(s)(t)(x)	14.47(n)	22.27	25.13	11.08	27.95	2.94(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	0.45(a)	0.46	0.47	0.47	0.49	0.49(c)
Expenses after expense reductions (f)	N/A	N/A	N/A	N/A	N/A	N/A
Net investment income (loss)	0.56(a)	0.61	0.85	0.98	1.03	0.99(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$1,164,430	$1,081,555	$448,834	$321,629	$306,546	$693,673

See Notes to Financial Statements

17

Financial Highlights – continued

Class R1	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$31.74	$28.43	$25.75	$25.11	$21.01	$21.98
Income (loss) from investment operations
Net investment income (loss) (d)	$(0.07)	$(0.11)	$(0.04)	$(0.01)	$0.01	$(0.00)(c)(w)
Net realized and unrealized gain (loss)	4.17	5.68	5.34	2.38	5.30	0.36
Total from investment operations	$4.10	$5.57	$5.30	$2.37	$5.31	$0.36
Less distributions declared to shareholders
From net investment income	$—	$—	$(0.08)	$(0.07)	$(0.03)	$(0.04)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.73)	$(2.26)	$(2.62)	$(1.73)	$(1.21)	$(1.33)
Net asset value, end of period (x)	$33.11	$31.74	$28.43	$25.75	$25.11	$21.01
Total return (%) (r)(s)(t)(x)	13.92(n)	21.04	23.89	9.98	26.67	1.92(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	1.45(a)	1.46	1.47	1.47	1.49	1.49(c)
Expenses after expense reductions (f)	1.45(a)	1.46	1.47	1.47	1.49	N/A
Net investment income (loss)	(0.44)(a)	(0.39)	(0.15)	(0.02)	0.03	(0.01)(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$34,098	$31,338	$31,740	$29,906	$31,074	$30,462

See Notes to Financial Statements

18

Financial Highlights – continued

Class R2	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$37.56	$33.08	$29.44	$28.44	$23.61	$24.52
Income (loss) from investment operations
Net investment income (loss) (d)	$0.01	$0.04	$0.10	$0.13	$0.13	$0.11(c)
Net realized and unrealized gain (loss)	4.99	6.70	6.23	2.70	6.00	0.42
Total from investment operations	$5.00	$6.74	$6.33	$2.83	$6.13	$0.53
Less distributions declared to shareholders
From net investment income	$—	$—	$(0.15)	$(0.17)	$(0.12)	$(0.15)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.73)	$(2.26)	$(2.69)	$(1.83)	$(1.30)	$(1.44)
Net asset value, end of period (x)	$39.83	$37.56	$33.08	$29.44	$28.44	$23.61
Total return (%) (r)(s)(t)(x)	14.18(n)	21.66	24.53	10.51	27.35	2.43(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	0.95(a)	0.96	0.97	0.97	0.99	0.99(c)
Expenses after expense reductions (f)	N/A	N/A	0.97	0.97	0.99	N/A
Net investment income (loss)	0.06(a)	0.12	0.35	0.46	0.53	0.49(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$103,263	$98,154	$108,772	$116,603	$199,581	$185,959

See Notes to Financial Statements

19

Financial Highlights – continued

Class R3	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$38.35	$33.72	$30.01	$28.96	$24.03	$24.93
Income (loss) from investment operations
Net investment income (loss) (d)	$0.06	$0.12	$0.18	$0.21	$0.20	$0.17(c)
Net realized and unrealized gain (loss)	5.09	6.85	6.33	2.75	6.09	0.43
Total from investment operations	$5.15	$6.97	$6.51	$2.96	$6.29	$0.60
Less distributions declared to shareholders
From net investment income	$(0.05)	$(0.08)	$(0.26)	$(0.25)	$(0.18)	$(0.21)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.78)	$(2.34)	$(2.80)	$(1.91)	$(1.36)	$(1.50)
Net asset value, end of period (x)	$40.72	$38.35	$33.72	$30.01	$28.96	$24.03
Total return (%) (r)(s)(t)(x)	14.32(n)	22.00	24.83	10.79	27.61	2.71(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	0.70(a)	0.71	0.72	0.72	0.74	0.74(c)
Expenses after expense reductions (f)	N/A	N/A	0.72	0.72	N/A	N/A
Net investment income (loss)	0.31(a)	0.36	0.60	0.73	0.78	0.74(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$644,358	$630,579	$605,466	$585,524	$493,211	$405,222

See Notes to Financial Statements

20

Financial Highlights – continued

Class R4	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$39.21	$34.43	$30.60	$29.49	$24.44	$25.34
Income (loss) from investment operations
Net investment income (loss) (d)	$0.11	$0.21	$0.26	$0.29	$0.27	$0.23(c)
Net realized and unrealized gain (loss)	5.21	6.99	6.45	2.79	6.20	0.43
Total from investment operations	$5.32	$7.20	$6.71	$3.08	$6.47	$0.66
Less distributions declared to shareholders
From net investment income	$(0.15)	$(0.16)	$(0.34)	$(0.31)	$(0.24)	$(0.27)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.88)	$(2.42)	$(2.88)	$(1.97)	$(1.42)	$(1.56)
Net asset value, end of period (x)	$41.65	$39.21	$34.43	$30.60	$29.49	$24.44
Total return (%) (r)(s)(t)(x)	14.45(n)	22.29	25.12	11.07	27.96	2.95(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	0.45(a)	0.46	0.47	0.47	0.49	0.49(c)
Expenses after expense reductions (f)	N/A	N/A	N/A	N/A	N/A	N/A
Net investment income (loss)	0.56(a)	0.61	0.85	0.97	1.03	0.98(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$922,482	$845,653	$775,528	$633,571	$836,470	$727,479

See Notes to Financial Statements

21

Financial Highlights – continued

Class R6	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$40.24	$35.27	$31.28	$30.10	$24.92	$25.82
Income (loss) from investment operations
Net investment income (loss) (d)	$0.13	$0.24	$0.30	$0.32	$0.31	$0.27(c)
Net realized and unrealized gain (loss)	5.36	7.18	6.60	2.86	6.32	0.42
Total from investment operations	$5.49	$7.42	$6.90	$3.18	$6.63	$0.69
Less distributions declared to shareholders
From net investment income	$(0.18)	$(0.19)	$(0.37)	$(0.34)	$(0.27)	$(0.30)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.91)	$(2.45)	$(2.91)	$(2.00)	$(1.45)	$(1.59)
Net asset value, end of period (x)	$42.82	$40.24	$35.27	$31.28	$30.10	$24.92
Total return (%) (r)(s)(t)(x)	14.52(n)	22.40	25.23	11.19	28.11	3.02(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	0.36(a)	0.37	0.37	0.38	0.39	0.38(c)
Expenses after expense reductions (f)	N/A	N/A	N/A	N/A	N/A	N/A
Net investment income (loss)	0.65(a)	0.70	0.95	1.07	1.13	1.10(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$2,455,089	$2,285,191	$1,685,286	$1,163,525	$1,411,776	$614,343

See Notes to Financial Statements

22

Financial Highlights – continued

Class 529A	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$38.13	$33.55	$29.89	$28.86	$23.96	$24.88
Income (loss) from investment operations
Net investment income (loss) (d)	$0.05	$0.11	$0.17	$0.21	$0.20	$0.17(c)
Net realized and unrealized gain (loss)	5.06	6.81	6.30	2.73	6.07	0.41
Total from investment operations	$5.11	$6.92	$6.47	$2.94	$6.27	$0.58
Less distributions declared to shareholders
From net investment income	$(0.06)	$(0.08)	$(0.27)	$(0.25)	$(0.19)	$(0.21)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.79)	$(2.34)	$(2.81)	$(1.91)	$(1.37)	$(1.50)
Net asset value, end of period (x)	$40.45	$38.13	$33.55	$29.89	$28.86	$23.96
Total return (%) (r)(s)(t)(x)	14.28(n)	21.96	24.80	10.76	27.60	2.65(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	0.75(a)	0.76	0.77	0.77	0.84	0.84(c)
Expenses after expense reductions (f)	0.74(a)	0.74	0.75	0.75	0.76	0.75(c)
Net investment income (loss)	0.29(a)	0.33	0.57	0.71	0.76	0.72(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$52,312	$42,906	$31,774	$24,393	$19,684	$14,831

See Notes to Financial Statements

23

Financial Highlights – continued

Class 529B	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$31.61	$28.14	$25.56	$24.89	$20.83	$21.83
Income (loss) from investment operations
Net investment income (loss) (d)	$0.04	$0.09	$(0.02)	$0.04	$(0.00)(w)	$(0.01)(c)
Net realized and unrealized gain (loss)	4.14	5.64	5.28	2.35	5.27	0.36
Total from investment operations	$4.18	$5.73	$5.26	$2.39	$5.27	$0.35
Less distributions declared to shareholders
From net investment income	$(0.06)	$—	$(0.14)	$(0.06)	$(0.03)	$(0.06)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.79)	$(2.26)	$(2.68)	$(1.72)	$(1.21)	$(1.35)
Net asset value, end of period (x)	$33.00	$31.61	$28.14	$25.56	$24.89	$20.83
Total return (%) (r)(s)(t)(x)	14.28(n)	21.89	24.01	10.17	26.69	1.87(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	0.75(a)	0.76	1.39	1.28	1.59	1.59(c)
Expenses after expense reductions (f)	0.75(a)	0.76	1.39	1.28	1.54	1.54(c)
Net investment income (loss)	0.26(a)	0.32	(0.06)	0.17	(0.02)	(0.06)(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$669	$677	$706	$577	$577	$567

See Notes to Financial Statements

24

Financial Highlights – continued

Class 529C	Six months ended	Year ended
	5/31/21 (unaudited)	11/30/20	11/30/19	11/30/18	11/30/17	11/30/16
Net asset value, beginning of period	$30.99	$27.82	$25.26	$24.70	$20.70	$21.71
Income (loss) from investment operations
Net investment income (loss) (d)	$(0.07)	$(0.12)	$(0.05)	$(0.02)	$(0.00)(w)	$(0.01)(c)
Net realized and unrealized gain (loss)	4.05	5.55	5.23	2.32	5.22	0.35
Total from investment operations	$3.98	$5.43	$5.18	$2.30	$5.22	$0.34
Less distributions declared to shareholders
From net investment income	$—	$—	$(0.08)	$(0.08)	$(0.04)	$(0.06)
From net realized gain	(2.73)	(2.26)	(2.54)	(1.66)	(1.18)	(1.29)
Total distributions declared to shareholders	$(2.73)	$(2.26)	$(2.62)	$(1.74)	$(1.22)	$(1.35)
Net asset value, end of period (x)	$32.24	$30.99	$27.82	$25.26	$24.70	$20.70
Total return (%) (r)(s)(t)(x)	13.87(n)	21.00	23.85	9.88	26.68	1.85(c)
Ratios (%) (to average net assets) and Supplemental data:
Expenses before expense reductions (f)	1.50(a)	1.51	1.52	1.52	1.59	1.59(c)
Expenses after expense reductions (f)	1.50(a)	1.51	1.52	1.52	1.53	1.53(c)
Net investment income (loss)	(0.48)(a)	(0.43)	(0.20)	(0.07)	(0.02)	(0.06)(c)
Portfolio turnover	10(n)	39	23	18	24	24
Net assets at end of period (000 omitted)	$6,314	$6,685	$6,197	$5,590	$6,034	$4,860

(a)	Annualized.
(c)	Amount reflects a one-time reimbursement of expenses by the custodian (or former custodian) without which net investment income and performance would be lower and expenses would be higher.
(d)	Per share data is based on average shares outstanding.
(f)	Ratios do not reflect reductions from fees paid indirectly, if applicable.
(n)	Not annualized.
(r)	Certain expenses have been reduced without which performance would have been lower.
(s)	From time to time the fund may receive proceeds from litigation settlements, without which performance would be lower.
(t)	Total returns do not include any applicable sales charges.
(w)	Per share amount was less than $0.01.
(x)	The net asset values and total returns have been calculated on net assets which include adjustments made in accordance with U.S. generally accepted accounting principles required at period end for financial reporting purposes.

See Notes to Financial Statements

25

Notes to Financial Statements

(unaudited)

(1) Business and Organization

Massachusetts Investors Growth Stock Fund (the fund) is organized as a Massachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as a diversified open-end management investment company.

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.

(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 March 2020, the FASB issued Accounting Standards Update 2020-04, Reference Rate Reform (Topic 848) – Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”), which provides optional, temporary relief for certain reference rate-related contract modifications due to the planned discontinuation of the London Interbank Offered Rate (LIBOR) and other IBOR-based reference rates as of the end of 2021. In March 2021, the administrator for LIBOR announced the extension of the publication of the more commonly used U.S. dollar LIBOR settings to the end of June 2023. Management is still evaluating the impact of ASU 2020-04 on the fund's accounting for investments, derivatives, debt and other contracts that will undergo reference rate-related modifications as a result of the reference rate reform.

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, or similar 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 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 — Equity securities, including restricted equity securities, are generally valued at the last sale or official closing price on their primary market or exchange as provided by a third-party pricing service. Equity securities, for which there were no sales reported that day, are generally valued at the last quoted daily bid quotation on their primary market or exchange as provided by a third-party pricing

26

Notes to Financial Statements (unaudited) - continued

service. Short-term instruments with a maturity at issuance of 60 days or less may be valued at amortized cost, which approximates market value. Open-end investment companies are generally valued at net asset value per share. Securities and other assets generally valued on the basis of information from a third-party pricing service may also be valued at a broker/dealer bid quotation. In determining values, third-party pricing services can utilize both transaction data and market information such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, and other market data. The values of foreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bid and asked prices for rates provided by a third-party pricing service.

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 of Trustees. Under the fund’s valuation policies and procedures, market quotations are not considered to be readily available for most types of debt instruments and floating rate loans and many types of derivatives. These investments are generally valued at fair value based on information from third-party pricing services. In addition, investments may be valued at fair value if the adviser determines that an investment’s value has been materially affected by events occurring after the close of the exchange or market on which the investment is principally traded (such as foreign exchange or market) and prior to the determination of the fund’s net asset value, or after the halt of trading of a specific security where trading does not resume prior to the close of the exchange or market on which the security is principally traded. Events that occur after foreign markets close (such as developments in foreign markets and significant movements in the U.S. markets) and prior to the determination of the fund’s net asset value may be deemed to have a material effect on the value of securities traded in foreign markets. Accordingly, the fund’s foreign equity securities may often be valued at fair value. The adviser generally relies on third-party pricing services or other information (such as the correlation with price movements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; the business and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and at what value to fair value an investment. The value of an investment for purposes of calculating the fund’s net asset value can differ depending on the source and method used to determine value. When fair valuation is used, the value of an investment used to determine the fund’s net asset value may differ from quoted or published prices for the same investment. There can be no assurance that the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which the fund determines its net asset value per share.

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

27

Notes to Financial Statements (unaudited) - continued

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 May 31, 2021 in valuing the fund's assets or liabilities:

Financial Instruments	Level 1	Level 2	Level 3	Total
Equity Securities	$10,459,095,560	$—	$—	$10,459,095,560
Mutual Funds	19,595,279	—	—	19,595,279
Total	$10,478,690,839	$—	$—	$10,478,690,839

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

Foreign Currency Translation — Purchases and sales of foreign investments, income, and expenses are converted into U.S. dollars based upon currency exchange rates prevailing on the respective dates of such transactions or on the reporting date for foreign denominated receivables and payables. Gains and losses attributable to foreign currency exchange rates on sales of securities are recorded for financial statement purposes as net realized gains and losses on investments. Gains and losses attributable to foreign exchange rate movements on receivables, payables, income and expenses are recorded for financial statement purposes as foreign currency transaction gains and losses. That portion of both realized and unrealized gains and losses on investments that results from fluctuations in foreign currency exchange rates is not separately disclosed.

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. Dividends received in cash are recorded on the ex-dividend date. Certain dividends from foreign securities will be recorded when the fund is informed of the dividend if such information is obtained subsequent to the ex-dividend date. Dividend payments received in additional securities are recorded on the ex-dividend date in an amount equal to the value of the security on such date.

The fund may receive proceeds from litigation settlements. Any proceeds received from litigation involving portfolio holdings are reflected in the Statement of Operations in realized gain/loss if the security has been disposed of by the fund or in unrealized gain/loss if the security is still held by the fund. Any other proceeds from litigation not related to portfolio holdings are reflected as other income in the Statement of Operations.

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. For the six months ended May 31, 2021, custody fees were not reduced.

28

Notes to Financial Statements (unaudited) - continued

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. Foreign taxes, if any, have been accrued by the fund in the accompanying financial statements in accordance with the applicable foreign tax law. Foreign income taxes may be withheld by certain countries in which the fund invests. Additionally, capital gains realized by the fund on securities issued in or by certain foreign countries may be subject to capital gains tax imposed by those countries.

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.

Book/tax differences primarily relate to wash sale loss deferrals, treating a portion of the proceeds from redemptions as a distribution for tax purposes, and partnership adjustments.

The tax character of distributions made during the current period will be determined at fiscal year end. The tax character of distributions declared to shareholders for the last fiscal year is as follows:

	Year ended 11/30/20
Ordinary income (including any short-term capital gains)	$37,892,124
Long-term capital gains	534,999,799
Total distributions	$572,891,923

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

As of 5/31/21
Cost of investments	$5,140,913,653
Gross appreciation	5,338,805,683
Gross depreciation	(1,028,497)
Net unrealized appreciation (depreciation)	$5,337,777,186
As of 11/30/20
Undistributed ordinary income	22,311,440
Undistributed long-term capital gain	849,622,212
Other temporary differences	172,103
Net unrealized appreciation (depreciation)	4,581,898,843

The aggregate cost above includes prior fiscal year end tax adjustments, if applicable.

29

Notes to Financial Statements (unaudited) - continued

Multiple Classes of Shares of Beneficial Interest — The fund offers multiple classes of shares, which differ in their respective distribution, service, and program manager fees. The fund's income, realized and unrealized gain (loss), and common expenses are allocated to shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per share dividend rates are generally due to differences in separate class expenses. Class B and Class C shares will convert to Class A shares approximately eight years after purchase. Class 529B and Class 529C shares will convert to Class 529A shares approximately eight years after purchase. The fund’s distributions declared to shareholders as reported in the Statements of Changes in Net Assets are presented by class as follows:

	Six months ended 5/31/21	Year ended 11/30/20
Class A	$327,278,282	$304,911,210
Class B	3,135,470	3,537,755
Class C	7,043,495	6,972,102
Class I	77,258,478	31,096,058
Class R1	2,695,590	2,530,870
Class R2	7,061,414	7,239,188
Class R3	45,204,742	42,000,598
Class R4	61,766,221	54,572,689
Class R6	164,783,144	117,259,821
Class 529A	3,131,629	2,218,187
Class 529B	59,688	56,321
Class 529C	585,197	497,124
Total	$700,003,350	$572,891,923

(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. The management fee is computed daily and paid monthly at an annual rate of 0.33% of the fund’s average daily net assets.

Distributor — MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, as distributor, received $187,460 and $16,779 for the six months ended May 31, 2021, as its portion of the initial sales charge on sales of Class A and Class 529A shares of the fund, respectively.

The Board of Trustees has adopted a distribution plan for certain share classes pursuant to Rule 12b-1 of the Investment Company Act of 1940.

The fund's distribution plan provides that the fund will pay MFD for services provided by MFD and financial intermediaries in connection with the distribution and servicing of certain share classes. One component of the plan is a distribution fee paid to MFD and another component of the plan is a service fee paid to MFD. MFD may subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries.

30

Notes to Financial Statements (unaudited) - continued

Distribution Plan Fee Table:

	Distribution Fee Rate (d)	Service Fee Rate (d)	Total Distribution Plan (d)	Annual Effective Rate (e)	Distribution and Service Fee
Class A	—	0.25%	0.25%	0.25%	$ 5,976,583
Class B	0.75%	0.25%	1.00%	1.00%	180,489
Class C	0.75%	0.25%	1.00%	1.00%	369,266
Class R1	0.75%	0.25%	1.00%	1.00%	164,025
Class R2	0.25%	0.25%	0.50%	0.50%	249,142
Class R3	—	0.25%	0.25%	0.25%	792,652
Class 529A	—	0.25%	0.25%	0.23%	59,964
Class 529B	0.75%	0.25%	1.00%	0.25%	846
Class 529C	0.75%	0.25%	1.00%	1.00%	30,545
Total Distribution and Service Fees					$7,823,512

(d) In accordance with the distribution plan for certain classes, the fund pays distribution and/or service fees equal to these annual percentage rates of each class’s average daily net assets. The distribution and service fee rates disclosed by class represent the current rates in effect at the end of the reporting period. Any rate changes, if applicable, are detailed below.

(e) The annual effective rates represent actual fees incurred under the distribution plan for the six months ended May 31, 2021 based on each class's average daily net assets. MFD has voluntarily agreed to rebate a portion of each class's 0.25% service fee attributable to accounts for which there is no financial intermediary specified on the account except for accounts attributable to MFS or its affiliates' seed money. For the six months ended May 31, 2021, this rebate amounted to $27,039, $74, $45, $2, $3,926, $8, and $20 for Class A, Class B, Class C, Class R1, Class 529A, Class 529B, and Class 529C, respectively, and is included in the reduction of total expenses in the Statement of Operations. For the six months ended May 31, 2021, the 0.75% distribution fee was not imposed for Class 529B shares due to the sales charge limitations contained in Financial Industry Regulatory Authority (“FINRA”) Rule 2341.

Certain Class A shares are subject to a contingent deferred sales charge (CDSC) in the event of a shareholder redemption within 18 months of purchase. Class B and Class 529B shares are subject to a CDSC in the event of a shareholder redemption within six years of purchase. Class C and Class 529C shares are subject to a CDSC in the event of a shareholder redemption within 12 months of purchase. All contingent deferred sales charges are paid to MFD and during the six months ended May 31, 2021, were as follows:

	Amount
Class A	$5,384
Class B	8,323
Class C	4,390
Class 529B	67
Class 529C	102

The fund has entered into and may from time to time enter into contracts with program managers and other parties which administer the tuition programs through which an investment in the fund’s 529 share classes is made. The fund has entered into an agreement with MFD pursuant to which MFD receives an annual fee of up to 0.05% of the average daily net assets attributable to each 529 share class. The services

31

Notes to Financial Statements (unaudited) - continued

provided by MFD, or a third party with which MFD contracts, include recordkeeping and tax reporting and account services, as well as services designed to maintain the program’s compliance with the Internal Revenue Code and other regulatory requirements. Program manager fees for the six months ended May 31, 2021, were as follows:

	Fee
Class 529A	$11,993
Class 529B	169
Class 529C	1,527
Total Program Manager Fees	$13,689

Shareholder Servicing Agent — MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fund for its services as shareholder servicing agent calculated as a percentage of the average daily net assets of the fund as determined periodically under the supervision of the fund's Board of Trustees. For the six months ended May 31, 2021, the fee was $552,190, which equated to 0.0109% annually of the fund's average daily net assets. MFSC also receives reimbursement from the fund for out-of-pocket expenses, sub-accounting and other shareholder servicing costs which may be paid to affiliated and unaffiliated service providers. Class R6 shares do not incur sub-accounting fees. For the six months ended May 31, 2021, these out-of-pocket expenses, sub-accounting and other shareholder servicing costs amounted to $3,712,478.

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 plus a fee based on average daily net assets. The administrative services fee incurred for the six months ended May 31, 2021 was equivalent to an annual effective rate of 0.0054% of the fund's average daily net assets.

Trustees’ and Officers’ Compensation — The fund pays 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 from MFS for their services to the fund. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

Prior to December 31, 2001, the fund had an unfunded defined benefit plan (“DB plan”) for independent Trustees. As of December 31, 2001, the Board took action to terminate the DB plan with respect to then-current and any future independent Trustees, such that the DB plan covers only certain of those former independent Trustees who retired on or before December 31, 2001. The DB plan resulted in a pension expense of $830 and is included in “Independent Trustees’ compensation” in the Statement of Operations for the six months ended May 31, 2021. The liability for deferred retirement benefits payable to those former independent Trustees under the DB plan amounted to $6,380 at May 31, 2021, and is included in “Payable for independent Trustees’ compensation” in the Statement of Assets and Liabilities.

32

Notes to Financial Statements (unaudited) - continued

Other — The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent with preservation of capital and liquidity. This money market fund does not pay a management fee to MFS but does incur investment and operating costs.

The fund is permitted to engage in purchase and sale transactions with funds and accounts for which MFS serves as investment adviser or sub-adviser (“cross-trades”) pursuant to a policy adopted by the Board of Trustees. This policy has been designed to ensure that cross-trades conducted by the fund comply with Rule 17a-7 under the Investment Company Act of 1940. During the six months ended May 31, 2021, the fund engaged in sale transactions pursuant to this policy, which amounted to $4,983,743. The sales transactions resulted in net realized gains (losses) of $658,265.

The adviser has voluntarily undertaken to reimburse the fund from its own resources on a quarterly basis for the cost of investment research embedded in the cost of the fund’s securities trades. This agreement may be rescinded at any time. For the six months ended May 31, 2021, this reimbursement amounted to $140,529, which is included in “Other” income in the Statement of Operations.

(4) Portfolio Securities

For the six months ended May 31, 2021, purchases and sales of investments, other than short-term obligations, aggregated $1,002,970,738 and $1,549,712,061, respectively.

(5) 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:

	Six months ended 5/31/21		Year ended 11/30/20
	Shares	Amount	Shares	Amount
Shares sold
Class A	4,686,093	$179,869,872	11,137,498	$361,647,905
Class B	1,824	56,361	8,118	227,130
Class C	165,897	5,269,646	465,091	12,545,198
Class I	1,397,723	56,165,694	20,682,323	722,205,561
Class R1	76,136	2,374,242	188,229	5,066,925
Class R2	218,052	8,171,111	737,981	23,122,884
Class R3	1,024,992	38,952,852	3,344,603	107,135,468
Class R4	3,353,578	127,883,289	4,230,230	138,041,980
Class R6	5,956,639	239,117,713	22,118,932	743,244,351
Class 529A	154,677	5,801,260	246,051	7,937,267
Class 529B	25	766	1,045	29,083
Class 529C	19,065	574,784	38,918	1,049,802
	17,054,701	$664,237,590	63,199,019	$2,122,253,554

33

Notes to Financial Statements (unaudited) - continued

	Six months ended 5/31/21		Year ended 11/30/20
	Shares	Amount	Shares	Amount
Shares issued to shareholders in reinvestment of distributions
Class A	7,917,346	$291,200,019	8,254,380	$268,929,062
Class B	101,183	3,074,941	125,864	3,458,746
Class C	228,204	6,878,078	227,210	6,196,008
Class I	1,814,562	69,044,094	788,094	26,503,823
Class R1	91,037	2,695,590	94,330	2,530,870
Class R2	196,695	6,988,569	209,427	6,615,817
Class R3	1,245,653	45,204,742	1,305,171	42,000,598
Class R4	1,116,708	41,407,537	1,110,745	36,454,869
Class R6	3,816,281	145,400,290	3,073,859	103,466,899
Class 529A	84,487	3,046,594	69,334	2,218,187
Class 529B	2,003	58,923	2,122	56,321
Class 529C	19,589	564,959	18,974	497,124
	16,633,748	$615,564,336	15,279,510	$498,928,324
Shares reacquired
Class A	(8,946,836)	$(346,072,958)	(31,601,790)	$(1,054,666,974)
Class B	(244,409)	(7,817,950)	(557,568)	(15,333,275)
Class C	(789,486)	(24,449,001)	(1,190,914)	(33,012,099)
Class I	(2,896,753)	(115,627,169)	(7,290,675)	(245,817,374)
Class R1	(124,447)	(3,867,102)	(411,784)	(10,736,521)
Class R2	(435,409)	(16,128,112)	(1,622,452)	(51,302,047)
Class R3	(2,890,149)	(110,479,134)	(6,158,796)	(198,855,134)
Class R4	(3,891,984)	(151,082,595)	(6,296,706)	(209,295,681)
Class R6	(9,222,388)	(371,391,900)	(16,182,133)	(552,788,355)
Class 529A	(71,415)	(2,709,145)	(137,042)	(4,475,711)
Class 529B	(3,168)	(98,445)	(6,852)	(180,914)
Class 529C	(58,525)	(1,727,705)	(64,940)	(1,685,932)
	(29,574,969)	$(1,151,451,216)	(71,521,652)	$(2,378,150,017)

34

Notes to Financial Statements (unaudited) - continued

	Six months ended 5/31/21		Year ended 11/30/20
	Shares	Amount	Shares	Amount
Net change
Class A	3,656,603	$124,996,933	(12,209,912)	$(424,090,007)
Class B	(141,402)	(4,686,648)	(423,586)	(11,647,399)
Class C	(395,385)	(12,301,277)	(498,613)	(14,270,893)
Class I	315,532	9,582,619	14,179,742	502,892,010
Class R1	42,726	1,202,730	(129,225)	(3,138,726)
Class R2	(20,662)	(968,432)	(675,044)	(21,563,346)
Class R3	(619,504)	(26,321,540)	(1,509,022)	(49,719,068)
Class R4	578,302	18,208,231	(955,731)	(34,798,832)
Class R6	550,532	13,126,103	9,010,658	293,922,895
Class 529A	167,749	6,138,709	178,343	5,679,743
Class 529B	(1,140)	(38,756)	(3,685)	(95,510)
Class 529C	(19,871)	(587,962)	(7,048)	(139,006)
	4,113,480	$128,350,710	6,956,877	$243,031,861

Effective June 1, 2019, purchases of the fund’s Class B and Class 529B shares are closed to new and existing investors subject to certain exceptions. Please see the fund’s prospectus for details.

(6) Line of Credit

The fund and certain other funds managed by MFS participate in a $1.25 billion unsecured committed line of credit of which $1 billion is reserved for use by the fund and certain other MFS U.S. funds. The line of credit is provided by a syndicate 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 highest of one month LIBOR, the Federal Funds Effective Rate and the Overnight Bank Funding Rate, 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. 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 rates equal to customary reference rates plus an agreed upon spread. For the six months ended May 31, 2021, the fund’s commitment fee and interest expense were $21,006 and $0, respectively, and are included in “Miscellaneous” expense in the Statement of Operations.

35

Notes to Financial Statements (unaudited) - continued

(7) Investments in Affiliated Issuers

An affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a company which is under common control. For the purposes of this report, the following were affiliated issuers:

Affiliated Issuers	Beginning Value	Purchases	Sales Proceeds	Realized Gain (Loss)	Change in Unrealized Appreciation or Depreciation	Ending Value
MFS Institutional Money Market Portfolio	$46,230,454	$752,592,704	$779,227,879	$—	$—	$19,595,279

Affiliated Issuers	Dividend Income	Capital Gain Distributions
MFS Institutional Money Market Portfolio	$15,919	$—

(8) Impacts of COVID-19

The pandemic related to the global spread of novel coronavirus disease (COVID-19), which was first detected in December 2019, has resulted in significant disruptions to global business activity and the global economy, as well as the economies of individual countries, the financial performance of individual companies and sectors, and the securities and commodities markets in general. Multiple surges in cases globally, the availability and widespread adoption of vaccines, and the emergence of variant strains of the virus continue to create uncertainty as to the future and long-term impacts resulting from the pandemic including impacts to the prices and liquidity of the fund's investments and the fund's performance.

36

Statement Regarding Liquidity Risk Management Program

The fund has adopted and implemented a liquidity risk management program (the “Program”) as required by Rule 22e-4 under the Investment Company Act of 1940, as amended. The fund’s Board of Trustees (the “Board”) has designated MFS as the administrator of the Program. The Program is reasonably designed to assess and manage the liquidity risk of the fund. Liquidity risk is the risk that the fund could not meet requests to redeem shares issued by the fund without significant dilution of remaining investors' interests.

MFS provided a written report to the Board for consideration at its April 2021 meeting that addressed the operation of the Program and provided an assessment of the adequacy and effectiveness of the Program during the period from January 1, 2020 to December 31, 2020 (the “Covered Period”). The report concluded that during the Covered Period the Program had operated effectively and had adequately and effectively been implemented to assess and manage the fund’s liquidity risk. MFS also reported that there were no liquidity events that impacted the fund or its ability to timely meet redemptions without dilution to existing shareholders during the Covered Period.

There can be no assurance that the Program will achieve its objectives in the future. Further information on liquidity risk, and other principal risks to which an investment in the fund may be subject, can be found in the prospectus.

37

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/proxyvoting, 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/proxyvoting, or by visiting the SEC’s Web site at http://www.sec.gov.

Quarterly Portfolio Disclosure

The fund files a complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year as an exhibit to its reports on Form N-PORT. The fund's Form N-PORT reports are available on the SEC's Web site at  http://www.sec.gov. A shareholder can obtain the portfolio holdings report for the first and third quarters of the fund's fiscal year at mfs.com/openendfunds by choosing the fund's name and then scrolling to the “Resources” section and clicking on the “Prospectus and Reports” tab.

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 at https://www.mfs.com/announcements or at mfs.com/openendfunds by choosing the fund’s name and then scrolling to the “Resources” section and clicking on the “Announcements” tab, if any.

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.

Provision of Financial Reports and Summary Prospectuses

The fund produces financial reports every six months and updates its summary prospectus and prospectus annually. To avoid sending duplicate copies of materials to households, only one copy of the fund’s annual and semiannual report and summary prospectus may be mailed to shareholders having the same last name and residential address on the fund’s records. However, any shareholder may contact MFSC (please see back cover for address and telephone number) to request that copies of these reports and summary prospectuses be sent personally to that shareholder.

38

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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 219341

Kansas City, MO 64121-9341

OVERNIGHT MAIL

MFS Service Center, Inc.

Suite 219341

430 W 7th Street

Kansas City, MO 64105-1407

Item 1(b):

Not applicable

ITEM 2. CODE OF ETHICS.

During the period covered by this report, the Registrant has not amended any provision in its Code of Ethics (the “Code”) that relates to an element of the Code’s definition enumerated in paragraph (b) of Item 2 of this Form N-CSR. During the period covered by this report, the Registrant did not grant a waiver, including an implicit waiver, from any provision of the Code.

ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT.

Not applicable for semi-annual reports.

ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES.

Not applicable for semi-annual reports.

ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS.

Not applicable to the Registrant.

ITEM 6. INVESTMENTS

A schedule of investments for Massachusetts Investors Growth Stock Fund is included as part of the report to shareholders under Item 1(a) 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 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) (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. Not applicable.

(2) A separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Act (17 CFR 270.30a-2): Attached hereto as EX-99.302CERT.

(3) Any written solicitation to purchase securities under Rule 23c-1 under the Act (17 CFR 270.23c-1) sent or given during the period covered by the report by or on behalf of the registrant to 10 or more persons. Not applicable.

(4) Change in the registrant’s independent public accountant. Not applicable.

(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 as EX-99.906CERT.

Notice

A copy of the Amended and Restated 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) MASSACHUSETTS INVESTORS GROWTH STOCK FUND

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

Date: July 16, 2021

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)*	/S/ DAVID L. DILORENZO
	David L. DiLorenzo, President (Principal Executive Officer)

Date: July 16, 2021

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

Date: July 16, 2021

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

EX-99.CERT

EX-99.302CERT

MASSACHUSETTS INVESTORS GROWTH STOCK FUND

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 Massachusetts Investors Growth Stock Fund;

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 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: July 16, 2021	/S/ JAMES O. YOST
	James O. Yost
	Treasurer (Principal Financial Officer and Accounting Officer)

EX-99.302CERT

MASSACHUSETTS INVESTORS GROWTH STOCK FUND

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 Massachusetts Investors Growth Stock Fund;

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 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: July 16, 2021	/S/ DAVID L. DILORENZO
	David L. DiLorenzo
	President (Principal Executive Officer)

EX-99.906CERT

EX-99.906CERT

MASSACHUSETTS INVESTORS GROWTH STOCK FUND

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 Massachusetts Investors Growth Stock Fund (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: July 16, 2021	/S/ 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

MASSACHUSETTS INVESTORS GROWTH STOCK FUND

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 Massachusetts Investors Growth Stock Fund (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: July 16, 2021	/S/ 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.