MFS MID CAP GROWTH SERIES - Ohio National Online · The opinions expressed in this letter are subject to change and may not be relied upon for ... As a contract holder of the fund,

SEMIANNUAL REPORTJune 30, 2017

MFS®

MID CAPGROWTH SERIESMFS® Variable Insurance Trust

VMG-SEM

MFS® MID CAP GROWTH SERIES

CONTENTS

Letter from the Executive Chairman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Portfolio composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Expense table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Portfolio of investments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Statement of assets and liabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Statement of operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Statements of changes in net assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Financial highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Notes to financial statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Results of shareholder meeting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Proxy voting policies and information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Quarterly portfolio disclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Further information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Information about fund contracts and legal claims . . . . . . . . . . . . . . . . . . . . . . . 19

The report is prepared for the general information of contract owners. It isauthorized for distribution to prospective investors only when preceded oraccompanied by a current prospectus.

NOT FDIC INSURED ‰ MAY LOSE VALUE ‰ NO BANK OR CREDIT UNION GUARANTEE ‰

NOT A DEPOSIT ‰ NOT INSURED BY ANY FEDERAL GOVERNMENT AGENCY OR NCUA/NCUSIF

MFS Mid Cap Growth Series

LETTER FROM THE EXECUTIVE CHAIRMAN

Dear Contract Owners:

Despite policy uncertainty accompanying a new presidential administration in the UnitedStates and unease over ongoing Brexit negotiations, most markets have proved resilient.U.S. share prices have reached new highs. The U.S. Federal Reserve has continued togradually hike interest rates. However, rates in most developed markets remain verylow, with major non-U.S. central banks just beginning to contemplate curbingaccommodative monetary policies.

Globally, economic growth has shown signs of recovery, led by China, the U.S. and theeurozone. Despite better growth, there are few immediate signs of worrisome inflationas wage growth remains muted. Europe has benefited from diminishing event risks asestablishment candidates won both the Dutch and French elections, averting a fearedpopulist trend. Emerging market economies are recovering at a somewhat slower paceamid fears that restrictive U.S. trade policies could further hamper the restrained pace ofglobal trade growth. Looking ahead, markets will have to contend with issues involvinggeopolitical hot spots on the Korean peninsula and in the Middle East, which couldpotentially lead to a clash of interests between the U.S. and other major powers such asChina or Russia.

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

Respectfully,

Robert J. ManningExecutive ChairmanMFS Investment Management

August 16, 2017

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

1


PORTFOLIO COMPOSITION

Portfolio structure

Equities 98.4%

Cash & CashEquivalents 1.6%

Top ten holdingsBright Horizons Family Solutions, Inc. 2.6%Roper Technologies, Inc. 2.5%NVIDIA Corp. 2.3%Amphenol Corp., “A” 2.2%C.R. Bard, Inc. 2.1%PerkinElmer, Inc. 2.1%SBA Communications Corp., REIT 1.9%Electronic Arts, Inc. 1.9%Henry Schein, Inc. 1.9%AMETEK, Inc. 1.7%

Equity sectorsTechnology 14.8%Industrial Goods & Services 14.5%Health Care 14.1%Special Products & Services 12.8%Leisure 12.4%Financial Services 8.0%Autos & Housing 6.1%Consumer Staples 5.4%Retailing 3.5%Basic Materials 3.3%Utilities & Communications 1.9%Transportation 0.8%Energy 0.8%

Cash & Cash Equivalents includes any cash, investments in money market funds, short-term securities, and other assets less liabilities. Please see theStatement 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 June 30, 2017.

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

2


EXPENSE TABLE

Fund Expenses Borne by the Contract Holders during the Period,January 1, 2017 through June 30, 2017As a contract holder of the fund, you incur ongoing costs, including management fees; distribution and/or service (12b-1) fees; andother fund expenses. This example is intended to help you understand your ongoing costs (in dollars) of investing in the fund and tocompare 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 periodJanuary 1, 2017 through June 30, 2017.

Actual ExpensesThe first line for each share class in the following table provides information about actual account values and actual expenses. Youmay 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 resultby the number in the first line under the heading entitled “Expenses Paid During Period” to estimate the expenses you paid on youraccount during this period.

Hypothetical Example for Comparison PurposesThe second line for each share class in the following table provides information about hypothetical account values and hypotheticalexpenses based on the fund’s actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not thefund’s actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balanceor expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the fund and otherfunds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reportsof the other funds.

Please note that the expenses shown in the table are meant to highlight the fund’s ongoing costs only and do not take into accountthe fees and expenses imposed under the variable contracts through which your investment in the fund is made. Therefore, thesecond line for each share class in the table is useful in comparing ongoing costs associated with an investment in vehicles (such asthe fund) which fund benefits under variable annuity and variable life insurance contracts and to qualified pension and retirementplans only, and will not help you determine the relative total costs of investing in the fund through variable annuity and variable lifeinsurance contracts. If the fees and expenses imposed under the variable contracts were included, your costs would have beenhigher.

Share ClassAnnualized

Expense Ratio

BeginningAccount Value

1/01/17

EndingAccount Value

6/30/17

Expenses PaidDuring Period (p)1/01/17-6/30/17

Initial ClassActual 0.81% $1,000.00 $1,148.24 $4.31

Hypothetical (h) 0.81% $1,000.00 $1,020.78 $4.06

Service ClassActual 1.06% $1,000.00 $1,146.83 $5.64

Hypothetical (h) 1.06% $1,000.00 $1,019.54 $5.31

(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 theperiod, multiplied by 181/365 (to reflect the one-half year period).

3


PORTFOLIO OF INVESTMENTS – 6/30/17 (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 – 98.4%Aerospace – 1.7%Harris Corp. 31,722 $ 3,460,236Leidos Holdings, Inc. 48,011 2,481,688TransDigm Group, Inc. 3,194 858,771

$ 6,800,695

Alcoholic Beverages – 1.7%Constellation Brands, Inc., “A” 35,046 $ 6,789,462

Automotive – 0.7%LKQ Corp. (a) 88,162 $ 2,904,938

Biotechnology – 2.6%Alexion Pharmaceuticals, Inc. (a) 16,269 $ 1,979,449Biomarin Pharmaceutical, Inc. (a) 41,872 3,802,815Regeneron Pharmaceuticals, Inc. (a) 9,179 4,508,174

$ 10,290,438

Broadcasting – 1.3%Netflix, Inc. (a) 34,627 $ 5,173,620

Brokerage & Asset Managers – 3.1%Blackstone Group LP 88,112 $ 2,938,535Intercontinental Exchange, Inc. 56,770 3,742,278NASDAQ, Inc. 79,187 5,661,079

$ 12,341,892

Business Services – 8.3%CoStar Group, Inc. (a) 4,644 $ 1,224,158Equifax, Inc. 41,864 5,752,951Fidelity National Information Services, Inc. 45,655 3,898,937Fiserv, Inc. (a) 51,071 6,248,026FleetCor Technologies, Inc. (a) 24,952 3,598,328Global Payments, Inc. 67,283 6,077,001Tyler Technologies, Inc. (a) 7,627 1,339,835Verisk Analytics, Inc., “A” (a) 50,416 4,253,598

$ 32,392,834

Cable TV – 1.5%Altice USA, Inc. (a) 24,030 $ 776,169Charter Communications, Inc., “A” (a) 15,368 5,176,711

$ 5,952,880

Chemicals – 0.2%Ingevity Corp. (a) 13,179 $ 756,475

Computer Software – 4.1%Autodesk, Inc. (a) 60,265 $ 6,075,917Cadence Design Systems, Inc. (a) 163,952 5,490,753Cloudera, Inc. (a)(l) 8,412 134,760PTC, Inc. (a) 55,701 3,070,239Sabre Corp. 51,356 1,118,020

$ 15,889,689

Computer Software – Systems – 4.4%Guidewire Software, Inc. (a) 23,572 $ 1,619,632NICE Systems Ltd., ADR 21,627 1,702,478


COMMON STOCKS – continuedComputer Software – Systems – continuedPresidio, Inc. (a)(l) 64,845 $ 927,932ServiceNow, Inc. (a) 30,029 3,183,074SS&C Technologies Holdings, Inc. 143,708 5,519,824Vantiv, Inc., “A” (a) 68,003 4,307,310

$ 17,260,250

Construction – 5.4%Armstrong World Industries, Inc. (a) 33,246 $ 1,529,316Lennox International, Inc. 24,647 4,526,175Pool Corp. 38,101 4,479,535Siteone Landscape Supply, Inc. (a) 80,376 4,184,374Vulcan Materials Co. 50,015 6,335,900

$ 21,055,300

Consumer Products – 1.9%Newell Brands, Inc. 111,782 $ 5,993,751Scotts Miracle-Gro Co. 17,983 1,608,759

$ 7,602,510

Consumer Services – 4.6%Bright Horizons Family Solutions, Inc. (a) 133,446 $ 10,303,366Nord Anglia Education, Inc. (a) 111,832 3,642,368Priceline Group, Inc. (a) 1,533 2,867,507ServiceMaster Global Holdings, Inc. (a) 30,901 1,211,010

$ 18,024,251

Containers – 1.5%CCL Industries, Inc. 69,380 $ 3,510,195Crown Holdings, Inc. (a) 39,036 2,328,888

$ 5,839,083

Electrical Equipment – 5.6%Acuity Brands, Inc. 3,514 $ 714,326AMETEK, Inc. 112,431 6,809,946Amphenol Corp., “A” 117,125 8,646,167Mettler-Toledo International, Inc. (a) 9,814 5,775,932

$ 21,946,371

Electronics – 5.1%Inphi Corp. (a) 46,567 $ 1,597,248M/A-COM Technology Solutions Holdings,Inc. (a) 24,167 1,347,794Mellanox Technologies Ltd. (a) 19,087 826,467Mercury Systems, Inc. (a) 2,203 92,724Monolithic Power Systems, Inc. 37,136 3,579,910NVIDIA Corp. 61,775 8,930,194Silicon Laboratories, Inc. (a) 55,899 3,820,697

$ 20,195,034

Energy – Independent – 0.8%Energen Corp. (a) 32,850 $ 1,621,804Parsley Energy, Inc., “A” (a) 52,597 1,459,567

$ 3,081,371

4


Portfolio of Investments (unaudited) – continued


COMMON STOCKS – continuedEntertainment – 0.9%Six Flags Entertainment Corp. 61,802 $ 3,684,017

Food & Beverages – 1.8%Blue Buffalo Pet Products, Inc. (a) 69,708 $ 1,590,039Chr. Hansen Holding A.S. 39,526 2,874,740Monster Worldwide, Inc. (a) 48,207 2,394,924

$ 6,859,703

Gaming & Lodging – 2.2%MGM Mirage 132,989 $ 4,161,226Paddy Power Betfair PLC 16,393 1,746,517Vail Resorts, Inc. 14,093 2,858,483

$ 8,766,226

General Merchandise – 1.6%Dollar Tree, Inc. (a) 44,451 $ 3,108,014Five Below, Inc. (a) 62,827 3,101,769

$ 6,209,783

Insurance – 1.6%Aon PLC 47,275 $ 6,285,211

Internet – 1.2%LogMeIn, Inc. 32,891 $ 3,437,109Wix.com Ltd. (a) 16,538 1,151,045

$ 4,588,154

Leisure & Toys – 2.9%Electronic Arts, Inc. (a) 69,340 $ 7,330,625Take-Two Interactive Software, Inc. (a) 56,661 4,157,784

$ 11,488,409

Machinery & Tools – 6.5%Colfax Corp. (a) 64,254 $ 2,529,680Flowserve Corp. 62,624 2,907,632Roper Technologies, Inc. 42,932 9,940,046SPX FLOW, Inc. (a) 28,611 1,055,174WABCO Holdings, Inc. (a) 44,706 5,700,462Xylem, Inc. 57,123 3,166,328

$ 25,299,322

Medical & Health Technology & Services – 2.7%Healthcare Services Group, Inc. 66,379 $ 3,108,529Henry Schein, Inc. (a) 39,875 7,297,922

$ 10,406,451

Medical Equipment – 8.8%C.R. Bard, Inc. 26,193 $ 8,279,869Cooper Cos., Inc. 18,026 4,315,785DexCom, Inc. (a) 25,433 1,860,424Edwards Lifesciences Corp. (a) 25,197 2,979,293Integra LifeSciences Holdings Corp. (a) 22,082 1,203,690PerkinElmer, Inc. 119,606 8,149,953QIAGEN N.V. 26,244 879,961Steris PLC 44,232 3,604,908VWR Corp. (a) 103,955 3,431,555

$ 34,705,438


COMMON STOCKS – continuedOther Banks & Diversified Financials – 2.5%First Republic Bank 41,238 $ 4,127,924Mastercard, Inc., “A” 42,367 5,145,472Zions Bancorporation 15,611 685,479

$ 9,958,875

Pollution Control – 0.7%Clean Harbors, Inc. (a) 47,816 $ 2,669,567

Railroad & Shipping – 0.8%Kansas City Southern Co. 30,510 $ 3,192,872

Real Estate – 0.8%Extra Space Storage, Inc., REIT 38,111 $ 2,972,658

Restaurants – 3.5%Aramark 107,287 $ 4,396,621Domino’s Pizza Group PLC 294,446 1,127,110Domino’s Pizza, Inc. 12,259 2,593,146Dunkin Brands Group, Inc. 44,481 2,451,793Panera Bread Co., “A” (a) 10,139 3,190,135

$ 13,758,805

Specialty Chemicals – 1.6%Axalta Coating Systems Ltd. (a) 100,729 $ 3,227,357Univar, Inc. (a) 100,128 2,923,738

$ 6,151,095

Specialty Stores – 1.9%Lululemon Athletica, Inc. (a) 23,542 $ 1,404,751O’Reilly Automotive, Inc. (a) 9,299 2,034,063Ross Stores, Inc. 48,193 2,782,182Tractor Supply Co. 22,772 1,234,470

$ 7,455,466

Telecommunications – Wireless – 1.9%SBA Communications Corp., REIT (a) 55,605 $ 7,501,115

Total Common Stocks(Identified Cost, $249,016,265) $386,250,260

MONEY MARKET FUNDS – 1.7%MFS Institutional Money Market Portfolio,0.98% (v) (Identified Cost, $6,663,943) 6,664,598 $ 6,664,598

COLLATERAL FOR SECURITIES LOANED – 0.1%State Street Navigator Securities LendingGovernment Money Market Portfolio,1% (j) (Identified Cost, $203,512) 203,512 $ 203,512

Total Investments(Identified Cost, $255,883,720) $393,118,370

OTHER ASSETS, LESS LIABILITIES – (0.2)% (654,670)

NET ASSETS – 100.0% $392,463,700

5


Portfolio of Investments (unaudited) – continued

(a) Non-income producing security.

(j) The rate quoted is the annualized seven-day yield of the fund at period end.

(l) A portion of this security is on loan.

(v) Underlying affiliated fund that is available only to investment companies managed by MFS. The rate quoted for the MFS Institutional Money MarketPortfolio 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

PLC Public Limited Company

REIT Real Estate Investment Trust

See Notes to Financial Statements

6


FINANCIAL STATEMENTS | STATEMENT OF ASSETS AND LIABILITIES (unaudited)

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

At 6/30/17

Assets

InvestmentsNon-affiliated issuers, at value (identified cost, $249,219,777) $386,453,772Underlying affiliated funds, at value (identified cost, $6,663,943) 6,664,598

Total investments, at value, including $198,416 of securities on loan (identified cost, $255,883,720) $393,118,370

Foreign currency, at value (identified cost, $5,343) 5,359Receivables for

Fund shares sold 56,678Interest and dividends 105,570

Other assets 967

Total assets $393,286,944

Liabilities

Payables for fund shares reacquired $538,720Collateral for securities loaned, at value 203,512Payable to affiliates

Investment adviser 16,429Shareholder servicing costs 727Distribution and/or service fees 1,314

Payable for independent Trustees’ compensation 456Accrued expenses and other liabilities 62,086

Total liabilities $823,244

Net assets $392,463,700

Net assets consist of

Paid-in capital $210,322,488Unrealized appreciation (depreciation) on investments and translation of assets and liabilities in foreign currencies 137,236,363Accumulated net realized gain (loss) on investments and foreign currency 44,914,807Accumulated net investment loss (9,958)

Net assets $392,463,700

Shares of beneficial interest outstanding 43,520,376

Net assetsShares

outstandingNet asset value

per shareInitial Class $297,130,578 32,519,719 $9.14Service Class 95,333,122 11,000,657 8.67


7


FINANCIAL STATEMENTS | STATEMENT OF OPERATIONS (unaudited)

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

Six months ended 6/30/17

Net investment loss

IncomeDividends $1,252,747Dividends from underlying affiliated funds 16,655Interest 867Foreign taxes withheld (3,883)

Total investment income $1,266,386

ExpensesManagement fee $1,453,997Distribution and/or service fees 114,472Shareholder servicing costs 10,780Administrative services fee 36,030Independent Trustees’ compensation 4,813Custodian fee 10,989Shareholder communications 20,771Audit and tax fees 27,727Legal fees 2,181Miscellaneous 11,554

Total expenses $1,693,314

Reduction of expenses by investment adviser (14,880)

Net expenses $1,678,434

Net investment loss $(412,048)

Realized and unrealized gain (loss) on investments and foreign currency

Realized gain (loss) (identified cost basis)Investments:

Non-affiliated issuers $22,368,560Underlying affiliated funds (486)

Foreign currency 1,978

Net realized gain (loss) on investments and foreign currency $22,370,052

Change in unrealized appreciation (depreciation)Investments $31,651,748Translation of assets and liabilities in foreign currencies 2,253

Net unrealized gain (loss) on investments and foreign currency translation $31,654,001

Net realized and unrealized gain (loss) on investments and foreign currency $54,024,053

Change in net assets from operations $53,612,005


8


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 ended6/30/17

(unaudited)Year ended

12/31/16Change in net assets

From operations

Net investment income (loss) $(412,048) $401,570Net realized gain (loss) on investments and foreign currency 22,370,052 24,066,750Net unrealized gain (loss) on investments and foreign currency translation 31,654,001 (6,122,501)

Change in net assets from operations $53,612,005 $18,345,819

Distributions declared to shareholders

From net realized gain on investments $— $(30,751,813)

Change in net assets from fund share transactions $(42,902,810) $(17,601,424)

Total change in net assets $10,709,195 $(30,007,418)

Net assets

At beginning of period 381,754,505 411,761,923At end of period (including accumulated net investment loss of $9,958 and

undistributed net investment income of $402,090, respectively) $392,463,700 $381,754,505


9


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.

Initial Class Six monthsended

6/30/17

Years ended 12/31

2016 2015 2014 2013 2012(unaudited)

Net asset value, beginning of period $7.96 $8.21 $8.76 $9.00 $6.56 $5.63

Income (loss) from investment operations

Net investment income (loss) (d) $(0.01) $0.01(c) $(0.03) $(0.03) $(0.02) $(0.01)Net realized and unrealized gain (loss) on investments and

foreign currency 1.19 0.41 0.39 0.80 2.49 0.94

Total from investment operations $1.18 $0.42 $0.36 $0.77 $2.47 $0.93

Less distributions declared to shareholders

From net realized gain on investments $— $(0.67) $(0.91) $(1.01) $(0.03) $—

Net asset value, end of period (x) $9.14 $7.96 $8.21 $8.76 $9.00 $6.56

Total return (%) (k)(r)(s)(x) 14.82(n) 4.91(c) 4.61 8.86 37.72 16.52

Ratios (%) (to average net assets)and Supplemental data:

Expenses before expense reductions (f) 0.81(a) 0.75(c) 0.81 0.81 0.81 0.89Expenses after expense reductions (f) 0.81(a) 0.74(c) 0.80 0.80 0.81 0.89Net investment income (loss) (0.15)(a) 0.15(c) (0.33) (0.34) (0.26) (0.10)Portfolio turnover 13(n) 37 37 49 62 65Net assets at end of period (000 omitted) $297,131 $294,226 $324,754 $363,788 $393,212 $359,488

Service Class Six monthsended

6/30/17

Years ended 12/31

2016 2015 2014 2013 2012(unaudited)

Net asset value, beginning of period $7.56 $7.85 $8.43 $8.72 $6.38 $5.48

Income (loss) from investment operations

Net investment loss (d) $(0.02) $(0.01)(c) $(0.05) $(0.05) $(0.04) $(0.02)Net realized and unrealized gain (loss) on investments and

foreign currency 1.13 0.39 0.38 0.77 2.41 0.92

Total from investment operations $1.11 $0.38 $0.33 $0.72 $2.37 $0.90

Less distributions declared to shareholders

From net realized gain on investments $— $(0.67) $(0.91) $(1.01) $(0.03) $—

Net asset value, end of period (x) $8.67 $7.56 $7.85 $8.43 $8.72 $6.38

Total return (%) (k)(r)(s)(x) 14.68(n) 4.62(c) 4.43 8.56 37.22 16.42

Ratios (%) (to average net assets)and Supplemental data:

Expenses before expense reductions (f) 1.06(a) 0.99(c) 1.06 1.06 1.06 1.14Expenses after expense reductions (f) 1.06(a) 0.99(c) 1.05 1.05 1.06 1.14Net investment loss (0.40)(a) (0.08)(c) (0.57) (0.59) (0.51) (0.35)Portfolio turnover 13(n) 37 37 49 62 65Net assets at end of period (000 omitted) $95,333 $87,529 $87,008 $88,899 $90,854 $76,779


10


Financial Highlights – continued

(a) Annualized.

(c) Amount reflects a one-time reimbursement of expenses by the custodian (or former custodian) without which net investment income andperformance 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.

(k) The total return does not reflect expenses that apply to separate accounts. Inclusion of these charges would reduce the total return figures for allperiods shown.

(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.

(x) The net asset values and total returns have been calculated on net assets which include adjustments made in accordance with U.S. generallyaccepted accounting principles required at period end for financial reporting purposes.


11


NOTES TO FINANCIAL STATEMENTS (unaudited)

(1) Business and OrganizationMFS Mid Cap Growth Series (the fund) is a diversified series of MFS Variable Insurance Trust (the trust). The trust is organized as aMassachusetts business trust and is registered under the Investment Company Act of 1940, as amended, as an open-endmanagement investment company. The shareholders of each series of the trust are separate accounts of insurance companies, whichoffer variable annuity and/or life insurance products, and qualified retirement and pension plans.

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

(2) Significant Accounting PoliciesGeneral – The preparation of financial statements in conformity with U.S. generally accepted accounting principles requiresmanagement to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure ofcontingent assets and liabilities at the date of the financial statements and the reported amounts of increases and decreases in netassets from operations during the reporting period. Actual results could differ from those estimates. In the preparation of thesefinancial statements, management has evaluated subsequent events occurring after the date of the fund’s Statement of Assets andLiabilities 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 ReportingModernization (the “Rule”). The Rule, which introduces two new regulatory reporting forms for investment companies –Form N-PORT and Form N-CEN – also contains amendments to Regulation S-X which impact financial statement presentation,particularly the presentation of derivative investments. Although still evaluating the impacts of the Rule, management believes thatmany of the Regulation S-X amendments are consistent with the fund’s current financial statement presentation and expects thatthe fund will be able to comply with the Rule’s Regulation S-X amendments by the August 1, 2017 compliance date.

Balance Sheet Offsetting – The fund’s accounting policy with respect to balance sheet offsetting is that, absent an event of defaultby the counterparty or a termination of the agreement, the International Swaps and Derivatives Association (ISDA) MasterAgreement does not result in an offset of reported amounts of financial assets and financial liabilities in the Statement of Assets andLiabilities across transactions between the fund and the applicable counterparty. The fund’s right to setoff may be restricted orprohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which a specific master netting agreementcounterparty is subject. Balance sheet offsetting disclosures, to the extent applicable to the fund, have been included in the fund’sSignificant 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 officialclosing price on their primary market or exchange as provided by a third-party pricing service. Equity securities, for which there wereno sales reported that day, are generally valued at the last quoted daily bid quotation on their primary market or exchange asprovided by a third-party pricing service. Short-term instruments with a maturity at issuance of 60 days or less may be valued atamortized 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 abroker/dealer bid quotation. Values obtained from third-party pricing services can utilize both transaction data and marketinformation such as yield, quality, coupon rate, maturity, type of issue, trading characteristics, and other market data. The values offoreign securities and other assets and liabilities expressed in foreign currencies are converted to U.S. dollars using the mean of bidand 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’sinvestments (including any fair valuation) to the adviser pursuant to valuation policies and procedures approved by the Board. If theadviser determines that reliable market quotations are not readily available, investments are valued at fair value as determined ingood faith by the adviser in accordance with such procedures under the oversight of the Board of Trustees. Under the fund’svaluation policies and procedures, market quotations are not considered to be readily available for most types of debt instrumentsand floating rate loans and many types of derivatives. These investments are generally valued at fair value based on information fromthird-party pricing services. In addition, investments may be valued at fair value if the adviser determines that an investment’s valuehas been materially affected by events occurring after the close of the exchange or market on which the investment is principallytraded (such as foreign exchange or market) and prior to the determination of the fund’s net asset value, or after the halting oftrading of a specific security where trading does not resume prior to the close of the exchange or market on which the security isprincipally traded. Events that occur on a frequent basis after foreign markets close (such as developments in foreign markets andsignificant movements in the U.S. markets) and prior to the determination of the fund’s net asset value may be deemed to have amaterial effect on the value of securities traded in foreign markets. Accordingly, the fund’s foreign equity securities may often bevalued at fair value. The adviser generally relies on third-party pricing services or other information (such as the correlation with pricemovements of similar securities in the same or other markets; the type, cost and investment characteristics of the security; thebusiness and financial condition of the issuer; and trading and other market data) to assist in determining whether to fair value and

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Notes to Financial Statements (unaudited) – continued

at what value to fair value an investment. The value of an investment for purposes of calculating the fund’s net asset value can differdepending on the source and method used to determine value. When fair valuation is used, the value of an investment used todetermine the fund’s net asset value may differ from quoted or published prices for the same investment. There can be no assurancethat the fund could obtain the fair value assigned to an investment if it were to sell the investment at the same time at which thefund 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 broadlevels. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, aninvestment’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair valuemeasurement. The fund’s assessment of the significance of a particular input to the fair value measurement in its entirety requiresjudgment, and considers factors specific to the investment. Level 1 includes unadjusted quoted prices in active markets for identicalassets 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 ownassumptions in determining the fair value of investments. The following is a summary of the levels used as of June 30, 2017 invaluing the fund’s assets or liabilities:

Investments at Value Level 1 Level 2 Level 3 TotalEquity Securities $386,250,260 $— $— $386,250,260Mutual Funds 6,868,110 — — 6,868,110

Total Investments $393,118,370 $— $— $393,118,370

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

Of the level 1 investments presented above, equity investments amounting to $1,127,110 would have been considered level 2investments at the beginning of the period. The primary reason for changes in the classifications between levels 1 and 2 occurs whenforeign equity securities are fair valued using other observable market-based inputs in place of the closing exchange price due toevents occurring after the close of the exchange or market on which the investment is principally traded. The fund’s foreign equitysecurities may often be valued using other observable market-based inputs. The fund’s policy is to recognize transfers between thelevels as of the end of the period.

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

Security Loans – Under its Securities Lending Agency Agreement with the fund, State Street Bank and Trust Company (“StateStreet”), as lending agent, loans the securities of the fund to certain qualified institutions (the “Borrowers”) approved by the fund.Security loans can be terminated at the discretion of either the lending agent or the fund and the related securities must be returnedwithin the earlier of the standard trade settlement period for such securities or within three business days. The loans arecollateralized by cash and/or U.S. Treasury and federal agency obligations in an amount typically at least equal to the market value ofthe securities loaned. On loans collateralized by cash, the cash collateral is invested in a money market fund. The market value of theloaned securities is determined at the close of business of the fund and any additional required collateral is delivered to the fund onthe next business day. State Street provides the fund with indemnification against Borrower default. In the event of Borrowerdefault, State Street will, for the benefit of the fund, either purchase securities identical to those loaned or, when such purchase iscommercially impracticable, pay the fund the market value of the loaned securities. In return, State Street assumes the fund’s rightsto the related collateral. If the collateral value is less than the cost to purchase identical securities, State Street is responsible for theshortfall, but only to the extent that such shortfall is not due to a decline in collateral value resulting from collateral reinvestment forwhich the fund bears the risk of loss. At period end, the fund had investment securities on loan, all of which were classified as equitysecurities in the fund’s Portfolio of Investments, with a fair value of $198,416. The fair value of the fund’s investment securities onloan and a related liability of $203,512 for cash collateral received on securities loaned are both presented gross in the Statement ofAssets and Liabilities. The collateral received on securities loaned exceeded the value of securities on loan at period end. The liabilityfor cash collateral for securities loaned is carried at fair value, which is categorized as level 2 within the fair value hierarchy. A portionof the income generated upon investment of the collateral is remitted to the Borrowers, and the remainder is allocated between thefund and the lending agent. On loans collateralized by U.S. Treasury and/or federal agency obligations, a fee is received from theBorrower, and is allocated between the fund and the lending agent. Income from securities lending is included in “Interest” incomein the Statement of Operations. The dividend and interest income earned on the securities loaned is accounted for in the samemanner as other dividend and interest income.

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Indemnifications – Under the fund’s organizational documents, its officers and Trustees may be indemnified against certainliabilities and expenses arising out of the performance of their duties to the fund. Additionally, in the normal course of business, thefund enters into agreements with service providers that may contain indemnification clauses. The fund’s maximum exposure underthese 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 theaccrual basis. Dividends received in cash are recorded on the ex-dividend date. Certain dividends from foreign securities will berecorded when the fund is informed of the dividend if such information is obtained subsequent to the ex-dividend date. Dividendand interest payments received in additional securities are recorded on the ex-dividend or ex-interest date in an amount equal to thevalue of the security on such date.

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

Tax Matters and Distributions – The fund intends to qualify as a regulated investment company, as defined under Subchapter Mof the Internal Revenue Code, and to distribute all of its taxable income, including realized capital gains. As a result, no provision forfederal income tax is required. The fund’s federal tax returns, when filed, will remain subject to examination by the Internal RevenueService for a three year period. Management has analyzed the fund’s tax positions taken on federal and state tax returns for all opentax years and does not believe that there are any uncertain tax positions that require recognition of a tax liability. Foreign taxes, ifany, 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 fundon 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 inaccordance with income tax regulations, which may differ from U.S. generally accepted accounting principles. Certain capitalaccounts in the financial statements are periodically adjusted for permanent differences in order to reflect their tax character. Theseadjustments have no impact on net assets or net asset value per share. Temporary differences which arise from recognizing certainitems of income, expense, gain or loss in different periods for financial statement and tax purposes will reverse at some time in thefuture. Distributions in excess of net investment income or net realized gains are temporary overdistributions for financial statementpurposes resulting from differences in the recognition or classification of income or distributions for financial statement and taxpurposes.

Book/tax differences primarily relate to wash sale loss deferrals.

The tax character of distributions declared to shareholders for the last fiscal year is as follows:Year ended

12/31/16Long-term capital gains $30,751,813

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

As of 6/30/17

Cost of investments $256,384,595

Gross appreciation 139,020,867Gross depreciation (2,287,092)

Net unrealized appreciation (depreciation) $136,733,775

As of 12/31/16

Undistributed ordinary income 402,090Undistributed long-term capital gain 23,045,630Other temporary differences (540)Net unrealized appreciation (depreciation) 105,082,027

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

Multiple Classes of Shares of Beneficial Interest – The fund offers multiple classes of shares, which differ in their respectivedistribution and/or service fees. The fund’s income, realized and unrealized gain (loss), and common expenses are allocated to

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shareholders based on the daily net assets of each class. Dividends are declared separately for each class. Differences in per sharedividend rates are generally due to differences in separate class expenses. The fund’s distributions declared to shareholders asreported in the Statements of Changes in Net Assets are presented by class as follows:

From net realized gain oninvestments

Six Months Ended6/30/17

Year Ended12/31/16

Initial Class $— $23,710,487Service Class — 7,041,326

Total $— $30,751,813

(3) Transactions with AffiliatesInvestment Adviser – The fund has an investment advisory agreement with MFS to provide overall investment management andrelated administrative services and facilities to the fund. The management fee is computed daily and paid monthly at the followingannual rates:

First $1 billion of average daily net assets 0.75%Average daily net assets in excess of $1 billion 0.70%

MFS has agreed in writing to reduce its management fee by a specified amount if certain MFS mutual fund assets exceed thresholdsagreed to by MFS and the fund’s Board of Trustees. For the six months ended June 30, 2017, this management fee reductionamounted to $14,880, which is included in the reduction of total expenses in the Statement of Operations. The management feeincurred for the six months ended June 30, 2017 was equivalent to an annual effective rate of 0.74% of the fund’s average daily netassets.

Distributor – MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund. TheTrustees have adopted a distribution plan for the Service Class shares pursuant to Rule 12b-1 under the Investment Company Act of1940.

The fund’s distribution plan provides that the fund will pay MFD distribution and/or service fees equal to 0.25% per annum of itsaverage daily net assets attributable to Service Class shares as partial consideration for services performed and expenses incurred byMFD and financial intermediaries (including participating insurance companies that invest in the fund to fund variable annuity andvariable life insurance contracts, sponsors of qualified retirement and pension plans that invest in the fund, and affiliates of theseparticipating insurance companies and plan sponsors) in connection with the sale and distribution of the Service Class shares. MFDmay subsequently pay all, or a portion, of the distribution and/or service fees to financial intermediaries.

Shareholder Servicing Agent – MFS Service Center, Inc. (MFSC), a wholly-owned subsidiary of MFS, receives a fee from the fundfor its services as shareholder servicing agent. For the six months ended June 30, 2017, the fee was $9,625, which equated to0.0050% annually of the fund’s average daily net assets. MFSC also receives payment from the fund for out-of-pocket expenses paidby MFSC on behalf of the fund. For the six months ended June 30, 2017, these costs amounted to $1,155.

Administrator – MFS provides certain financial, legal, shareholder communications, compliance, and other administrative services tothe fund. Under an administrative services agreement, the fund reimburses MFS the costs incurred to provide these services. Thefund is charged an annual fixed amount of $17,500 plus a fee based on average daily net assets. The administrative services feeincurred for the six months ended June 30, 2017 was equivalent to an annual effective rate of 0.0186% of the fund’s average dailynet 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 directlyto Trustees or officers of the fund who are also officers of the investment adviser, all of whom receive remuneration for their servicesto the fund from MFS. Certain officers and Trustees of the fund are officers or directors of MFS, MFD, and MFSC.

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 IndependentSenior Officer (ISO) for the funds. Frank L. Tarantino serves as the ISO and is an officer of the funds and the sole member ofTarantino LLC. The funds can terminate the ISO Agreement with Tarantino LLC at any time under the terms of the ISO Agreement.For the six months ended June 30, 2017, the fee paid by the fund under this agreement was $365 and is included in“Miscellaneous” expense in the Statement of Operations. MFS has agreed to bear all expenses associated with office space, otheradministrative support, and supplies provided to the ISO.

The fund invests in the MFS Institutional Money Market Portfolio which is managed by MFS and seeks current income consistent withpreservation of capital and liquidity. This money market fund does not pay a management fee to MFS.

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The fund is permitted to engage in purchase and sale transactions with funds and accounts for which MFS serves as investmentadviser or sub-adviser (“cross-trades”) pursuant to a policy adopted by the Board of Trustees. This policy has been designed toensure that cross-trades conducted by the fund comply with Rule 17a-7 under the Investment Company Act of 1940. Under thispolicy, cross-trades are effected at current market prices with no remuneration paid in connection with the transaction. During thesix months ended June 30, 2017, the fund engaged in purchase and sale transactions pursuant to this policy, which amounted to$937,959 and $530,240, respectively. The sales transactions resulted in net realized gains (losses) of $(6,664).

(4) Portfolio SecuritiesFor the six months ended June 30, 2017, purchases and sales of investments, other than short-term obligations, aggregated$50,674,943 and $98,417,793, respectively.

(5) Shares of Beneficial InterestThe 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 6/30/17 Year ended 12/31/16Shares Amount Shares Amount

Shares soldInitial Class 224,272 $1,916,839 1,145,319 $9,157,568Service Class 913,265 7,450,486 2,367,351 18,135,281

1,137,537 $9,367,325 3,512,670 $27,292,849

Shares issued to shareholders in reinvestment of distributionsInitial Class — $— 2,909,262 $23,710,487Service Class — — 908,558 7,041,326

— $— 3,817,820 $30,751,813

Shares reacquiredInitial Class (4,647,033) $(40,111,578) (6,654,934) $(54,279,464)Service Class (1,485,170) (12,158,557) (2,788,211) (21,366,622)

(6,132,203) $(52,270,135) (9,443,145) $(75,646,086)

Net changeInitial Class (4,422,761) $(38,194,739) (2,600,353) $(21,411,409)Service Class (571,905) (4,708,071) 487,698 3,809,985

(4,994,666) $(42,902,810) (2,112,655) $(17,601,424)

The fund is one of several mutual funds in which certain MFS funds may invest. The MFS funds do not invest in the underlying fundsfor the purpose of exercising management or control. At the end of the period, the MFS Moderate Allocation Portfolio, the MFSGrowth Allocation Portfolio, and the MFS Conservative Allocation Portfolio were the owners of record of approximately 31%, 10%,and 6%, respectively, of the value of outstanding voting shares of the fund.

(6) Line of CreditThe 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 financingneeds. Interest is charged to each fund, based on its borrowings, generally at a rate equal to the higher of the Overnight FederalReserve funds rate or daily one month LIBOR plus an agreed upon spread. A commitment fee, based on the average daily, unusedportion 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 banksfor temporary financing needs. Interest is charged to each fund, based on its borrowings, at a rate equal to the Overnight FederalReserve funds rate plus an agreed upon spread. For the six months ended June 30, 2017, the fund’s commitment fee and interestexpense were $1,338 and $0, respectively, and are included in “Miscellaneous” expense in the Statement of Operations.

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(7) Transactions in Underlying Affiliated Funds – Affiliated IssuersAn affiliated issuer may be considered one in which the fund owns 5% or more of the outstanding voting securities, or a companywhich is under common control. For the purposes of this report, the fund assumes the following to be an affiliated issuer:

Underlying Affiliated Fund

BeginningShares/Par

Amount

AcquisitionsShares/Par

Amount

DispositionsShares/Par

Amount

EndingShares/Par

Amount

MFS Institutional Money Market Portfolio 2,584,523 49,865,216 (45,785,141) 6,664,598

Underlying Affiliated FundRealized

Gain (Loss)Capital GainDistributions

DividendIncome

EndingValue

MFS Institutional Money Market Portfolio $(486) $— $16,655 $6,664,598

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RESULTS OF SHAREHOLDER MEETING (unaudited)

At a special meeting of shareholders of MFS Variable Insurance Trust, which was held on March 23, 2017, the following action wastaken:

Item 1: To elect the following individuals as Trustees:

Number of Dollars

Nominee For Withheld Authority

Steven E. Buller 11,311,922,492.61 518,570,973.54John A. Caroselli 11,291,109,000.34 539,384,465.81Maureen R. Goldfarb 11,233,211,779.66 597,281,686.49David H. Gunning 11,179,077,201.17 651,416,264.98Michael Hegarty 11,191,993,154.78 638,500,311.37John P. Kavanaugh 11,242,238,261.44 588,255,204.71Robert J. Manning 11,314,479,376.58 516,014,089.57Clarence Otis, Jr. 11,208,873,448.85 621,620,017.30Maryanne L. Roepke 11,263,427,105.03 567,066,361.12Robin A. Stelmach 11,313,883,043.82 516,610,422.33Laurie J. Thomsen 11,240,219,041.09 590,274,425.06

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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, uponrequest, 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…” headeron 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 endedJune 30 is available by August 31 of each year without charge by visiting mfs.com (once you have selected “Individual Investor” asyour 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 thefirst and third quarters of each fiscal year on Form N-Q. The fund’s Form N-Q is available on the EDGAR database on theCommission’s Internet Web site at http://www.sec.gov, and may be reviewed and copied at the:

Public Reference RoomSecurities and Exchange Commission100 F Street, NE, Room 1580Washington, D.C. 20549

Information on the operation of the Public Reference Room may be obtained by calling the Commission at 1-800-SEC-0330. Copiesof the fund’s Form N-Q also may be obtained, upon payment of a duplicating fee, by electronic request at the following e-mailaddress: [email protected] 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). Thisinformation is available on mfs.com by following these steps once you have selected “Individual Investor” as your role: (1) Click onthe “Individual Investor Home” in the top navigation and then select the “Announcements” option within the “Market Outlooks”drop down, or (2) Click on “Products & Services” and “Variable Insurance Portfolios” and then select the fund’s name.

INFORMATION ABOUT FUND CONTRACTS AND LEGAL CLAIMS

The fund has entered into contractual arrangements with an investment adviser, administrator, distributor, shareholder servicingagent, 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 arenot intended to create any shareholder right to enforce them against the service providers or to seek any remedy under them againstthe 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 claimsagainst Trustees and Officers, must be brought in state and federal courts located within the Commonwealth of Massachusetts.

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Documents

MFS MID CAP GROWTH SERIES - Ohio National Online · The opinions expressed in this letter are subject to change and may not be relied upon for ... As a contract holder of the fund,