Prospectus by Investment Company (Form 497)

December 10, 2025 (As Amended March 5, 2026)

MFS^®Blended Research^®Emerging Markets Equity ETF

The investment objective of the fund is to seek capital appreciation.

TICKER SYMBOL
BREE

Table of contents

SUMMARY OF KEY INFORMATION	2
INVESTMENT OBJECTIVE, STRATEGIES, AND RISKS	5
MANAGEMENT OF THE FUND	8
ADDITIONAL INFORMATION ABOUT THE PURCHASE AND SALE OF FUND SHARES	10
OTHER INFORMATION	11
FINANCIAL HIGHLIGHTS	14

Principal U.S. Listing Exchange: The New York Stock Exchange LLC (the NYSE). Exchange-traded fund (ETF) shares are not individually redeemable.

The U.S. Securities and Exchange Commission (the SEC) has not approved or disapproved the fund's shares or determined whether this prospectus is accurate or complete. Anyone who tells you otherwise is committing a crime.

EBE-PRO-030526

Summary of Key Information

Investment Objective

The fund's investment objective is to seek capital appreciation.

Fees and Expenses

This table describes the fees and expenses that you may pay when you buy, hold, and sell shares of the fund. Investors may also pay commissions or other fees to their financial intermediaries when they buy, hold, and sell shares of the fund, which are not reflected below.

Shareholder Fees (fees paid directly from your investment):
	Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)		None
	Maximum Deferred Sales Charge(Load) (as a percentage of original purchase price or redemption proceeds, whichever is less)		None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment):
	Management Fee		0.44%
	Other Expenses		0.00%
	Total Annual Fund Operating Expenses		0.44%

1 The annual fund operating expenses are based on estimated "Other Expenses" for the current fiscal year expressed as a percentage of the fund's estimated average net assets during the period.

2

Example

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other funds. The example does not take into account brokerage commissions or other fees that you may pay to your financial intermediary when purchasing or selling shares of the fund.

The example assumes that: you invest $10,000 in the fund for the time periods indicated and you redeem your shares at the end of the time periods; your investment has a 5% return each year; and the fund's operating expenses remain the same.

Although your actual costs will likely be higher or lower, under these assumptions your costs would be:

			1 YEAR		3 YEARS
	Fund Shares		$45		$141

Portfolio Turnover

The fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when shares are held in a taxable account. These transaction costs, which are not reflected in "Annual Fund Operating Expenses" or in the "Example," affect the fund's performance. The portfolio turnover rate for the fund is not available because the fund had not commenced operations as of the date of this prospectus.

Principal Investment Strategies

MFS (Massachusetts Financial Services Company, the fund's investment adviser) seeks to achieve the fund's objective by actively identifying potential investments in issuers economically tied to emerging market countries based on fundamental and quantitative analysis and then constructing a portfolio from these potential investments while managing various risk factors (e.g., issuer, industry, and sector weightings, market capitalization, and volatility) compared to the MSCI Emerging Markets Index.

MFS normally invests at least 80% of the fund's net assets in equity securities of issuers that are tied economically to emerging market countries. Emerging markets are countries determined to have emerging market economies based on factors that demonstrate the country's financial and capital markets are in the development phase, including whether a particular country has a low- to middle-income economy according to the International Bank for Reconstruction and Development (the World Bank), the country's designation by the International Monetary Fund as an emerging market, or the country's inclusion in an emerging market index. Emerging market countries include countries located in Latin America, Asia, Africa, the Middle East, and developing countries of Europe, primarily Eastern Europe. Equity securities include common stocks, depositary receipts, and other securities that represent an ownership interest (or right to acquire an ownership interest) in a company or other issuer.

MFS may invest the fund's assets in securities of companies of any size.

MFS normally invests the fund's assets across different industries, sectors, countries, and regions, but MFS may invest a significant percentage of the fund's assets in issuers in a single industry, sector, country, or region.

MFS uses an active bottom-up approach to buying and selling investments for the fund. Investments are selected primarily based on blending fundamental and quantitative research. MFS uses fundamental analysis of individual issuers to determine a fundamental rating for an issuer. MFS uses quantitative analysis to determine a quantitative rating for an issuer. MFS combines the fundamental rating with the quantitative rating to create a blended rating for an issuer. When the fundamental rating is not available, MFS treats the issuer as having a neutral fundamental rating.

MFS constructs the portfolio using a portfolio optimization process that considersthe blended rating, as well as issuer, industry, and sector weightings, market capitalization, volatility, and other factors. The portfolio managers have the discretion to adjust the inputs and parameters used in the optimization process and the fund's portfolio holdings based on factors such as the desired portfolio characteristics and the portfolio managers' qualitative assessment of the optimization results. MFS' goal is to construct an actively managed portfolio with a targetpredicted tracking error of approximately 2% compared to the MSCI Emerging Markets Index. Tracking error generally measures how the differences between the fund's returns and the MSCI Emerging Markets Index's returns have varied over a period of time.

For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.

Principal Risks

As with any exchange-traded fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.

The principal risks of investing in the fund are:

Investment Selection Risk: MFS' investment analysis, its development and use of quantitative models, and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. The quantitative models used by MFS (both proprietary and third-party) may not produce the intended results for a variety of reasons, including the factors used in the models, the weight placed on each factor in the models, changes from the market factors' historical trends, changing sources of market return or market risk, and technical issues in the design, development, implementation, application, and maintenance of the models (e.g., incomplete, stale, or inaccurate data, human error, programming or other software issues, coding errors, and technology failures).

Equity Market Risk/Company Risk: Equity markets are volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single issuer or type of security, issuers within a broad market sector, industry or geographic region, or the equity markets in general. Certain events can have a dramatic adverse effect on equity markets and may lead to periods of high volatility in an equity market or a segment of an equity market. The value of an investment held by the fund may decline due to factors directly related to the issuer.

Investment Strategy Risk: There is no assurance that the fund's predicted tracking error will equal its target predicted tracking error at any point in time or consistently for any period of time, or that the fund's predicted tracking error and actual tracking error will be similar. The fund's strategy to target a predicted tracking error of approximately 2% compared to the MSCI Emerging Markets Index and to blend fundamental and quantitative research may not produce the intended results. In addition, MFS' fundamental research is not available for all issuers.

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Foreign Risk: Exposure to foreign markets through issuers or currencies can involve additional risks relating to market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These factors can make foreign investments, especially those tied economically to emerging markets or countries subject to sanctions or the threat of new or modified sanctions, more volatile and less liquid than U.S. investments. In addition, foreign markets can react differently to these conditions than the U.S. market.

Emerging Markets Risk:Investments tied economically to emerging markets, especially frontier markets, can involve additional and greater risks than the risks associated with investments in developed markets. Emerging markets can have less developed markets,greater custody and operational risk, less developed legal, regulatory, and accounting systems, greater government involvement in the economy, greater risk of new or inconsistent government treatment of or restrictions on issuers and instruments, and greater political, social, geopolitical, and economic instability than developed markets.

Currency Risk: The value of foreign currencies relative to the U.S. dollar fluctuates in response to market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions, and changes in currency exchange rates impact the financial condition of companies or other issuers and may change the value in U.S. dollars of investments denominated in foreign currencies.

Focus Risk: Issuers in a single industry, sector, country, or region can react similarly to market, currency, political, economic, regulatory, geopolitical, environmental, public health, and other conditions, and the fund's performance will be affected by the conditions in the industries, sectors, countries, and regions to which the fund is exposed. Furthermore, investments in particular industries, sectors, countries, or regions may be more volatile than the broader market as a whole.

Liquidity Risk: It may be difficult to value, and it may not be possible to sell, certain investments, types of investments, and/or investments in certain segments of the market, and the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs.

Capacity Risk: The markets and securities in which the fund primarily invests may, at times, have limited capacity, and as an ETF, the fund cannot be closed to new investors as a means of managing capacity. During periods of capacity constraints, the implementation and execution of the fund's strategy, including the portfolio securities purchased, held, and sold by the fund, may change, and capacity limitations may negatively impact the performance of the fund.

Fluctuation of Net Asset Value and Share Price Risk: The net asset value (NAV) per share of the fund will generally fluctuate with changes in the market value of the fund's holdings. The fund's shares can be bought and sold in the secondary market at market prices. Disruptions to purchases and sales, the existence of extreme market volatility, and/or a lack of an active trading market for the fund's shares may result in the fund's shares trading significantly above (at a premium) or below (at a discount) to NAV and bid/ask spreads may widen. Shares of the fund may trade at a larger premium or discount to the NAV than shares of other ETFs that focus on other market segments or types of securities. In addition, in stressed market conditions or periods of market disruption or volatility, the market for shares of the fund may become less liquid in response to deteriorating liquidity in the markets for the fund's underlying portfolio holdings. If you buy fund shares when their market price is at a premium or sell fund shares when their market prices is at a discount, you may pay more than, or receive less than, NAV, respectively.

Authorized Participant Risks: Only financial institutions authorized to transact daily with the fund (Authorized Participants) may engage in creation or redemption transactions directly with the fund, and Authorized Participants are not obligated to do so. To the extent an Authorized Participant cannot or is otherwise unwilling to engage in creation and redemption transactions, and no other Authorized Participant engages in such transactions, shares of the fund may trade at a significant discount or premium to NAV, experience wider intraday bid/ask spreads, and may face trading halts and/or delisting from the exchange.

Trading Issues Risk:There can be no assurance that an active trading market for the fund's shares will develop or be maintained. In addition, trading of the fund's shares may be halted or become less liquid. Shares of the fund, similar to shares of other issuers listed on a stock exchange, may be sold short and are therefore subject to the risk of increased volatility and price decreases associated with being sold short.

Most fund investors will buy and sell fund shares on the listing exchange or on another secondary market. When buying or selling shares of the fund, investors typically will pay brokerage commissions or other charges imposed by financial intermediaries as determined by that financial intermediary.

Cash Transactions Risk: Unlike certain ETFs that distribute portfolio securities entirely in-kind, the fund may effect some or all creations and redemptions using cash, rather than in-kind securities. As a result, an investment in the fund may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind.

Performance Information

The bar chart and performance table are not included because the fund has not had a full calendar year of operations. Once the fund has commenced operations, updated performance information will be available online at mfs.com. Past performance (before and after taxes) does not necessarily indicate how the fund will perform in the future.

Investment Adviser

MFS serves as the investment adviser for the fund.

Portfolio Manager(s)

Portfolio Manager	Since	Title
Jed Stocks	Inception	Investment Officer of MFS
Nathan Bryant	January 2026	Investment Officer of MFS
Jim Fallon	Inception	Investment Officer of MFS
Matt Krummell	Inception	Investment Officer of MFS
Jonathan Sage	Inception	Investment Officer of MFS
Jenney Zhang	January 2026	Investment Officer of MFS

Matt Krummell has announced his intention to retire effective April 7, 2027, and he will no longer be a portfolio manager of the fund as of that date.

Purchase and Sale of Fund Shares

The fund issues and redeems shares at NAV only with Authorized Participants and only in large blocks of shares (each, a Creation Unit). Individual fund shares may not be purchased or redeemed directly with the fund. An Authorized Participant may purchase or

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redeem a Creation Unit of the fund each business day that the fund is open in exchange for the delivery of a designated portfolio of in-kind securities and/or cash.

Shares are listed for trading on the NYSE, and individual fund shares may only be purchased and sold in the secondary market through a financial intermediary at market price. Because the fund's shares will trade at market prices rather than NAV, shares may trade at prices greater than NAV (at a premium), at NAV, or less than NAV (at a discount).

An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares (bid) and the lowest price a seller is willing to accept for shares (ask) when buying or selling fund shares in the secondary market (the bid/ask spread). Recent information, including information regarding the fund's NAV, market price, premiums and discounts, and bid/ask spread, is available at www.mfs.com.

Taxes

If your shares are held in a taxable account, the fund's distributions will be taxed to you as ordinary income and/or capital gains. However, if your shares are held in a tax-advantaged account, you will generally be taxed only upon withdrawals from the account unless such an account allows for tax-free withdrawals.

Payments to Broker/Dealers and Other Financial Intermediaries

The fund, MFS, and/or MFS' affiliates may pay financial intermediaries, which include banks, broker/dealers, or financial professionals, for the sale of shares of a fund and/or the servicing of shareholder accounts. These payments may create a conflict of interest by influencing your broker/dealer or other financial intermediary and your salesperson to recommend the fund over another investment. Ask your financial intermediary or visit your financial intermediary's website for more information.

Investment Objective, Strategies, and Risks

Investment Objective

The fund's investment objective is to seek capital appreciation. The fund's objective may be changed without shareholder approval.

Principal Investment Strategies

MFS seeks to achieve the fund's objective by actively identifying potential investments in issuers economically tied to emerging market countries based on fundamental and quantitative analysis and then constructing a portfolio from these potential investments while managing various risk factors (e.g., issuer, industry, and sector weightings, market capitalization, and volatility) compared to the MSCI Emerging Markets Index.

MFS normally invests at least 80% of the fund's net assets in equity securities of issuers that are tied economically to emerging market countries. Emerging markets are countries determined to have emerging market economies based on factors that demonstrate the country's financial and capital markets are in the development phase, including whether a particular country has a low- to middle-income economy according to the International Bank for Reconstruction and Development (the World Bank), the country's designation by the International Monetary Fund as an emerging market, or the country's inclusion in an emerging market index. Emerging market countries include countries located in Latin America, Asia, Africa, the Middle East, and developing countries of Europe, primarily Eastern Europe. Examples of emerging market countries include, but are not limited to, Argentina, Brazil, Chile, Hungary, India, Indonesia, Mexico, Panama, the People's Republic of China, Peru, Poland, Saudi Arabia, South Africa, South Korea, Taiwan, and Thailand. Equity securities include common stocks, depositary receipts, and other securities that represent an ownership interest (or right to acquire an ownership interest) in a company or other issuer.

MFS generally considers the issuer of a security or other investment to be tied economically to emerging market countries if: (i) the security or other investment is issued or guaranteed by the government of an emerging market country or any of its agencies, authorities or instrumentalities; (ii) the issuer is organized under the laws of, and maintains a principal office in, an emerging market country; (iii) the issuer has its principal securities trading market in an emerging market country; (iv) a third party has identified an emerging market country as the issuer's "country of risk"; (v) the issuer is included in an index which is representative of emerging market countries; (vi) the issuer derives 50% or more of its total revenues from goods sold or services performed in emerging market countries; or (vii) the issuer has 50% or more of its assets in emerging market countries.

MFS may invest the fund's assets in securities of companies of any size.

MFS normally invests the fund's assets across different industries, sectors, countries, and regions, but MFS may invest a significant percentage of the fund's assets in issuers in a single industry, sector, country, or region.

MFS uses an active bottom-up approach to buying and selling investments for the fund. Investments are selected primarily based on blending fundamental and quantitative research. MFS uses fundamental analysis of individual issuers and their potential in light of their financial condition and market, economic, political, and regulatory conditions to determine a fundamental rating for an issuer. Factors considered may include analysis of an issuer's earnings, cash flows, competitive position, and management ability. MFS may also consider environmental, social, and governance (ESG) factors in its fundamental investment analysis where MFS believes such factors could materially impact the economic value of an issuer. ESG factors considered may include, but are not limited to, climate change, resource depletion, an issuer's governance structure and practices, data protection and privacy issues, and diversity and labor practices. MFS uses quantitative analysis, including quantitative models that systematically evaluate an issuer's valuation, price and earnings momentum, earnings quality, and other factors, to determine a quantitative rating for an issuer. MFScombines the fundamental rating with the quantitative rating to create a blended rating for an issuer. (When the fundamental rating is not available, MFS treats the issuer as having a neutral fundamental rating. MFS' quantitative research generates ratings on a greater number of issuers than MFS' fundamental research.)

MFS constructs the portfolio using a portfolio optimization process that considersthe blended rating, as well as issuer, industry, and sector weightings, market capitalization, volatility, and other factors.The portfolio managers have the discretion to adjust the inputs and parameters used in the optimization process and the fund's portfolio holdings based on factors such as the desired portfolio characteristics and the portfolio managers' qualitative assessment of the optimization results. MFS' goal is to construct an actively managed portfolio with a targetpredicted tracking error of approximately 2% compared to the MSCI Emerging Markets Index. Tracking error generally measures how the differences between the fund's returns and the MSCI Emerging Markets Index's returns have varied over a period of time. A lower tracking error means that there is generally less variation between the fund's returns compared to the applicable index. Third-party quantitative risk models are

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used in the portfolio construction process and to measure the predicted tracking error of the fund's portfolio.

For purposes of the fund's 80% policy, net assets include the amount of any borrowings for investment purposes.

Principal Investment Type

The principal investment type in which the fund may invest is:

Equity Securities: Equity securities represent an ownership interest, or the right to acquire an ownership interest, in a company or other issuer. Different types of equity securities provide different voting and dividend rights and priorities in the event of bankruptcy of the issuer. Equity securities include common stocks, preferred stocks, securities convertible into stocks, equity interests in real estate investment trusts, and depositary receipts for such securities.

Principal Risks

The share price of the fund will change daily based on changes in market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. As with any exchange-traded fund, the fund may not achieve its objective and/or you could lose money on your investment in the fund. An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. The significance of any specific risk to an investment in the fund will vary over time depending on the composition of the fund's portfolio, market conditions, and other factors. You should read all of the risk information below carefully, because any one or more of these risks may result in losses to the fund.

The principal risks of investing in the fund are:

Investment Selection Risk: MFS' investment analysis, its development and use of quantitative models, and its selection of investments may not produce the intended results and/or can lead to an investment focus that results in the fund underperforming other funds with similar investment strategies and/or underperforming the markets in which the fund invests. The quantitative models used by MFS (both proprietary and third-party) may not produce the intended results for a variety of reasons, including the factors used in the models, the weight placed on each factor in the models, changes from the market factors' historical trends, changing sources of market return or market risk, and technical issues or errors in the design, development, implementation, application, and maintenance of the models (e.g., incomplete, stale, or inaccurate data, human error, programming or other software issues, coding errors, and technology failures). In addition, MFS or the fund's other service providers may experience disruptions or operating errors that could negatively impact the fund.

Equity Market Risk: Equity markets are volatile and can decline significantly in response to changes in, or investor perceptions of, issuer, market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. These conditions can affect a single issuer or type of security, issuers within a broad market sector, industry or geographic region, or the equity markets in general. Different parts of the market and different types of securities can react differently to these conditions. For example, the stocks of growth companies can react differently from the stocks of value companies, and the stocks of large cap companies can react differently from the stocks of small cap companies. Certain changes or events, such as political, social, or economic developments, including political elections, increasing or negative interest rates or the U.S. government's inability at times to agree on a long-term budget and deficit reduction plan (which has in the past resulted and may in the future result in a government shutdown); market closures and/or trading halts; government or regulatory actions, including sanctions, the imposition of tariffs or other protectionist actions and changes in fiscal, monetary, or tax policies; rapid technological developments or widespread adoption of emerging technologies (such as artificial intelligence); natural disasters; outbreaks of pandemic and epidemic diseases; terrorist attacks; war; and other geopolitical changes or events, can have a dramatic adverse effect on equity markets and may lead to periods of high volatility in an equity market or a segment of an equity market.

Company Risk: Changes in the financial condition of a company or other issuer, changes in specific market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions that affect a particular type of investment or issuer, and changes in general market, economic, political, regulatory, geopolitical, environmental, public health, and other conditions can adversely affect the prices of investments. The value of an investment held by the fund may decline due to factors directly related to the issuer, such as competitive pressures, rapid technological developments or widespread adoption of emerging technologies (such as artificial intelligence) impacting the issuer's competitive position and making products and/or services obsolete, cybersecurity incidents, financial leverage, historical and/or prospective earnings, management performance, labor and supply shortages, investor perceptions, and other factors. The prices of securities of smaller, less well-known issuers can be more volatile than the prices of securities of larger issuers or the market in general.

Investment Strategy Risk: There is no assurance that the fund's predicted tracking error will equal its target predicted tracking error at any point in time or consistently for any period of time, or that the fund's predicted tracking error and actual tracking error will be similar. The fund's strategy to target a predicted tracking error of approximately 2% compared to the MSCI Emerging Markets Index and to blend fundamental and quantitative research may not produce the intended results. In addition, MFS' fundamental research is not available for all issuers.

Foreign Risk: Investments in securities of foreign issuers, securities of companies with significant foreign exposure, and foreign currencies can involve additional risks relating to market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions. Political, social, diplomatic, and economic developments, U.S. and foreign government action, or the threat thereof, such as the imposition of currency or capital blockages, controls, or tariffs, economic and trade sanctions or embargoes, security trading suspensions, entering or exiting trade or other intergovernmental agreements, or the expropriation or nationalization of assets in a particular country, can cause dramatic declines in certain or all securities with exposure to that country and other countries. Sanctions, or the threat of sanctions, may cause volatility in regional and global markets and may negatively impact the performance of various sectors and industries, as well as companies in other countries, which could have a negative effect on the performance of the fund. In the event of nationalization, expropriation, confiscation or other government action, intervention, or restriction, the fund could lose its entire investment in a particular foreign issuer or country. Civil unrest, geopolitical tensions, armed conflicts, wars, and acts of terrorism are other potential risks that could adversely affect an investment in a foreign security or in foreign markets or issuers generally. Economies and financial markets are interconnected, which increases the likelihood that conditions in one country or region can adversely impact issuers in different countries and regions. Less stringent regulatory, accounting, auditing, and disclosure requirements for issuers and markets are more common in certain

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foreign countries. Enforcing legal rights can be difficult, costly, and slow in certain foreign countries and with respect to certain types of investments, and can be particularly difficult against foreign governments. Changes in currency exchange rates can significantly impact the financial condition of a company or other issuer with exposure to multiple countries as well as affect the U.S. dollar value of foreign currency investments and investments denominated in foreign currencies. Additional risks of foreign investments include trading, settlement, custodial, and other operational risks, and withholding and other taxes. These factors can make foreign investments, especially those tied economically to emerging markets, more volatile and less liquid than U.S. investments. In addition, foreign markets can react differently to market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions than the U.S. market. Investments in foreign issuers through depositary receipts generally involve risks applicable to other types of foreign investments. Investments in depositary receipts may be less liquid and more volatile than the underlying securities in their primary trading market.

Emerging Markets Risk: Investments tied economically to emerging markets, especially frontier markets (emerging markets that are early in their development), can involve additional and greater risks than the risks associated with investments in developed markets. Emerging markets typically have less developed economies and markets, greater custody and operational risk, less developed legal, regulatory, and accounting systems, less trading volume, less stringent investor protection and disclosure standards, less reliable settlement practices, greater government involvement in the economy, and greater risk of new or inconsistent government treatment of or restrictions on issuers and instruments than developed countries. Financial and other disclosures by emerging market issuers may be considerably less reliable than disclosures made by issuers in developed markets. In addition, the Public Company Accounting Oversight Board, which regulates auditors of U.S. public companies, may not be able to inspect audit work papers in certain emerging market countries. Emerging markets can also be subject to greater political, social, geopolitical, and economic instability and more susceptible to environmental problems. In addition, many emerging market countries with less established health care systems have experienced outbreaks of pandemics or contagious diseases from time to time. These factors can make emerging market investments more volatile and less liquid than investments in developed markets.

Currency Risk: Changes in currency exchange rates can significantly impact the financial condition of a company or other issuer with exposure to multiple countries. In addition, a decline in the value of a foreign currency relative to the U.S. dollar reduces the value of the foreign currency and investments denominated in that currency. In addition, the use of foreign exchange contracts to reduce foreign currency exposure can eliminate some or all of the benefit of an increase in the value of a foreign currency versus the U.S. dollar. The value of foreign currencies relative to the U.S. dollar fluctuates in response to, among other factors, interest rate changes, intervention (or failure to intervene) by the U.S. or foreign governments, central banks, or supranational entities such as the International Monetary Fund, the imposition of currency controls, and other political or regulatory conditions in the United States or abroad. Foreign currency values can decrease significantly both in the short term and over the long term in response to these and other conditions.

Focus Risk: Issuers in a single industry, sector, country, or region can react similarly to market, currency, political, economic, regulatory, geopolitical, environmental, public health, and other conditions. These conditions include business environment changes; economic factors such as fiscal, monetary, and tax policies; inflation and unemployment rates; and government and regulatory changes. The fund's performance will be affected by the conditions in the industries, sectors, countries, and regions to which the fund is exposed. Furthermore, investments in particular industries, sectors, countries, or regions may be more volatile than the broader market as a whole.

Liquidity Risk: Certain investments and types of investments are subject to restrictions on resale, may trade in the over-the-counter market, or may not have an active trading market due to adverse market, economic, industry, political, regulatory, geopolitical, environmental, public health, and other conditions, including trading halts, sanctions, or wars. Investors trying to sell large quantities of a particular investment or type of investment, or lack of market makers or other buyers for a particular investment or type of investment may also adversely affect liquidity. At times, all or a significant portion of a market may not have an active trading market. Without an active trading market, it may be difficult to value, and it may not be possible to sell, these investments and the fund could miss other investment opportunities and hold investments it would prefer to sell, resulting in losses for the fund. In addition, the fund may have to sell certain of these investments at prices or times that are not advantageous in order to meet redemptions or other cash needs, which could result in dilution of remaining investors' interests in the fund. The prices of illiquid securities may be more volatile than more liquid investments.

Capacity Risk: The markets and securities in which the fund primarily invests may, at times, have limited capacity, and as an ETF, the fund cannot be closed to new investors as a means of managing capacity. During periods of capacity constraints, the implementation and execution of the fund's strategy, including the portfolio securities purchased, held, and sold by the fund, may change, and capacity limitations may negatively impact the performance of the fund.

Fluctuation of Net Asset Value and Share Price Risk: The NAV of the fund's shares will generally fluctuate with changes in the market value of the fund's holdings. The fund's shares are listed on an exchange and can be bought and sold in the secondary market at market prices. The market prices of the fund's shares will fluctuate in accordance with changes in NAV and supply and demand of fund shares on the listing exchange. It is possible that the market price of fund shares and the fund's NAV will vary significantly. As a result, you may sustain losses if you pay more than the shares' NAV when you purchase shares, or receive less than the shares' NAV when you sell shares, in the secondary market. During the existence of extreme market volatility and/or a lack of an active trading market for the fund's shares, the market price of fund shares is more likely to diverge significantly from the fund's NAV. During such periods, you may be unable to sell your shares of the fund or may incur significant losses if you sell your shares. Disruptions at market makers, Authorized Participants or other market participants may also result in significant differences between the market price of the fund's shares and the fund's NAV.

The market price of shares during the trading day, like the price of any exchange-traded security, includes a bid/ask spread charged by the exchange specialist, market makers, or other participants that trade the particular security. In times of severe market disruption or volatility, the bid/ask spread can increase significantly. At those times, shares of the fund are most likely to be traded at a discount to NAV, and the discount is likely to be greatest when the price of fund shares is falling fastest. Securities held by the fund may be traded in markets that close at a different time than the listing exchange. During the time when the listing exchange is open but after the applicable market closing, fixing or settlement times,

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bid/ask spreads and the resulting premium or discount to the fund's NAV may widen.

Authorized Participant Risk: Only financial institutions authorized to transact daily with the fund (Authorized Participants) may engage in creation or redemption transactions directly with the fund, and Authorized Participants are not obligated to do so. The fund has a limited number of intermediaries that act as Authorized Participants. There are no obligations of market makers to make a market in the fund's shares or of Authorized Participants to submit creation or redemption orders for Creation Units. Decisions by market makers and/or Authorized Participants to reduce their role with respect to market making or creation and redemption activities during times of market stress, or a decline in the number of Authorized Participants due to decisions to exit the business, bankruptcy, or other factors, could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying value of the fund's portfolio securities and the market price of fund shares. To the extent an Authorized Participant cannot or is otherwise unwilling to engage in creation and redemption transactions, and no other Authorized Participant creates or redeems shares in such transactions, shares of the fund may trade at a significant discount or premium to NAV and may face trading halts and/or delisting from the exchange.

Trading Issues Risk: Although shares are listed on an exchange, there can be no assurance that an active secondary trading market will develop or continue. In addition, trading of shares in the secondary market may become less liquid or may be halted, for example, due to activation of market-wide "circuit breakers." If trading halts or an unanticipated early closing of the listing exchange occurs, a shareholder may be unable to purchase or sell shares of the fund. MFD, the distributor of the fund's shares, does not maintain a secondary market in the shares. There can be no assurance that requirements for the fund to remain listed on the exchange will be met or maintained. If the fund's shares are delisted from the listing exchange, MFS may seek to list the fund's shares on another exchange, merge the fund with another exchange-traded fund or mutual fund, or redeem the fund's shares at NAV. Shares of the fund, similar to shares of other issuers listed on a stock exchange, may be sold short and are therefore subject to the risk of increased volatility and price decreases associated with being sold short. Most fund investors will buy and sell fund shares on the listing exchange or on another secondary market. When buying or selling shares of the fund, investors typically will pay brokerage commissions or other charges imposed by financial intermediaries as determined by that financial intermediary.

Cash Transactions Risk:Unlike certain ETFs, the fund may effect some or all creations and redemptions using cash, rather than in-kind securities. Therefore, the fund may be required to sell portfolio securities and recognize gains on such sales that the fund might not have recognized if it were to distribute portfolio securities in-kind. As a result, an investment in the fund may be less tax-efficient than an investment in an ETF that distributes portfolio securities entirely in-kind. The use of cash creations and redemptions may also cause the fund's shares to trade in the market at greater bid/ask spreads or greater premiums or discounts to the fund's NAV. Furthermore, cash creation and redemption transactions may result in certain brokerage, tax, foreign exchange, execution, price movement and other costs, and expenses related to the execution of trades resulting from such transactions. To the extent that the maximum additional charge for creation or redemption transactions is insufficient to cover these costs and expenses, the fund's performance could be negatively impacted.

Other Investment Strategies and Risks

Active and Frequent Trading: MFS may engage in active and frequent trading in pursuing the fund's principal investment strategies. Frequent trading may increase transaction costs, which can reduce the fund's return. Frequent trading can also increase the possibility of capital gain and ordinary distributions. Frequent trading can also result in the realization of a higher percentage of short-term capital gains and a lower percentage of long-term capital gains as compared to a fund that trades less frequently. Because short-term capital gains are distributed as ordinary income, this would generally increase your tax liability unless you hold your shares through a tax-advantaged or tax-exempt vehicle.

Operational and Cybersecurity Risk: The fund and its service providers, and your ability to transact in fund shares, may be negatively impacted due to operational matters arising from, among other issues, human errors, systems and technology disruptions or failures, fraudulent activities, or cybersecurity incidents. Operational issues and cybersecurity incidents may cause the fund or its service providers, as well as securities trading venues and other market participants, to suffer data corruption and/or lose operational functionality, and could, among other things, impair the ability to calculate the fund's net asset value per share, impede trading of portfolio securities, and result in the theft, misuse, and/or improper release of confidential information relating to the fund or its shareholders. Such operational issues and cybersecurity incidents may result in losses to the fund and its shareholders. Because technology is frequently changing, new ways to carry out cyberattacks continue to develop. In addition, the rapid development and increasingly widespread use of new technologies, including machine learning technology and generative models could exacerbate these risks. Therefore, there is a chance that certain risks have not been identified or prepared for, or that an attack may not be detected, which puts limitations on the ability of the fund and its service providers to plan for or respond to a cyberattack. Information relating to the Fund's investments is delivered electronically, which can give rise to a number of risks, including, but not limited to, the risks that such communications may not be secure and may contain computer viruses or other defects, may not be accurately replicated on other systems, or may be intercepted, deleted or interfered with, without the knowledge of the sender or the intended recipient. Furthermore, geopolitical tensions could increase the scale and sophistication of deliberate cybersecurity attacks, particularly those from nation-states or from entities with nation-state backing.

Temporary Defensive Strategy:In response to adverse market, economic, industry, political, or other conditions, MFS may depart from the fund's principal investment strategies by temporarily investing for defensive purposes. When MFS invests defensively, different factors could affect the fund's performance and the fund may not achieve its investment objective. In addition, the defensive strategy may not work as intended.

Further Information on Investment Strategies, Types, and Risks:Information about investment strategies and investment types not described in the prospectus and the risks associated with those investment strategies and investment types are described in the fund's Statement of Additional Information (SAI).

Management of the Fund

Investment Adviser

MFS, located at 111 Huntington Avenue, Boston, Massachusetts 02199, serves as the investment adviser for the fund. Subject to the supervision of the fund's Board of Trustees, MFS is responsible for

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managing the fund's investments, executing transactions, and providing related administrative services (including certain financial, legal, and other administrative services) and facilities under an Investment Management Agreement between the fund and MFS.

The management fee set forth in the Investment Management Agreement is 0.44% of the fund's average daily net assets annually.

The management fee includes investment management services and ordinary, recurring operating expenses, except for certain expenses. The following expenses are excluded from the all-inclusive management fee: (i) interest expense or other costs of the fund's borrowing(s) or financing activities; (ii) taxes (including, but not limited to, income, excise, transfer and withholding taxes, including any accrued deferred tax liability) and governmental fees levied against the fund; (iii) costs of any litigation such as any indemnification obligation, attorneys' fees, expenses, costs, judgments, amounts paid in settlement, fines, penalties, fees of expert witnesses, document production fees, and all other liabilities incurred or paid by the fund or a person indemnified by a fund; (iv) costs associated with any tax reclaims or similar actions, including any fees paid on a contingent basis; (v) brokerage fees and commissions and other investment-related transaction costs incurred by or for the fund; (vi) expenses of a fund's securities lending, if any, including any securities lending agent fees, as governed by a separate securities lending agreement; (vii) expenses incident to meetings of fund shareholders and the associated preparation, filing, printing and mailing of related notices and proxy statements; (viii) expenses incurred in connection with the provision of distribution services under a plan adopted pursuant to Rule 12b-1 under the 1940 Act (if any); (ix) investment-related expenses (such as interest and borrowing expenses incurred in connection with the fund's investment activity, and fees and expenses associated with investments in investment companies and other similar investment vehicles); (x) expenses of a fund which are capitalized in accordance with generally accepted accounting principles; (xi) the fee paid to MFS pursuant to this Agreement; (xii) other nonrecurring or extraordinary expenses (as determined by a majority of the Trustees of the trust who are not "interested persons" of the trust); and (xiii) such other expenses as approved by a majority of the trust's Board of Trustees.

A discussion regarding the basis for the Board of Trustees' approval of the Investment Management Agreement will be available in the fund's Form N-CSR filing with the SEC for the period that ends February 28, 2026, and in the related financial statements posted online at etfs.mfs.com.

MFS is America's oldest mutual fund organization. MFS and its predecessor organizations have a history of money management dating from 1924 and the founding of the first mutual fund, Massachusetts Investors Trust. Net assets under the management of the MFS organization were approximately $651 billion as of December 31, 2025.

Disclosure of Portfolio Holdings. The fund has established a policy with respect to the disclosure of fund portfolio holdings. A description of this policy is provided in the SAI.

On each business day, before commencement of trading on the NYSE, the fund will disclose on www.mfs.com the identities and quantities of the fund's portfolio holdings that will form the basis for the fund's calculation of NAV at the end of the business day. Other information concerning the fund's portfolio holdings may also be published on the fund's website from time to time.

Portfolio Manager(s)

Information regarding the portfolio manager(s) of the fund is set forth below. Further information regarding the portfolio manager(s), including other accounts managed, compensation, ownership of fund shares, and possible conflicts of interest, is available in the fund's SAI.

Portfolio Manager	Primary Role	Five Year History
Jed Stocks	Lead Portfolio Manager	Employed in the investment area of MFS since 2001
Nathan Bryant	Portfolio Manager	Employed in the investment area of MFS since 2015
Jim Fallon	Portfolio Manager	Employed in the investment area of MFS since 1999
Matt Krummell	Portfolio Manager	Employed in the investment area of MFS since 2001
Jonathan Sage	Portfolio Manager	Employed in the investment area of MFS since 2000
Jenney Zhang	Portfolio Manager	Employed in the investment area of MFS since 2011

Matt Krummell has announced his intention to retire effective April 7, 2027, and he will no longer be a portfolio manager of the fund as of that date.

Administrator

MFS provides the fund with certain financial, legal, and other administrative services pursuant to an Investment Management Agreement. MFS bears the costs of the administrative services provided under the Investment Management Agreement.

Transfer Agent

State Street Bank and Trust Company (State Street) serves as the fund's transfer agent and dividend disbursing agent. MFS bears the costs of the services provided under the transfer agency agreement.

Distributor

MFS Fund Distributors, Inc. (MFD), a wholly-owned subsidiary of MFS, is the distributor of shares of the fund.

Distribution and Service Fees

The fund has adopted a plan in accordance with Rule 12b-1 under the Investment Company Act of 1940, as amended (the Distribution Plan). Under the Distribution Plan, the fund is authorized to pay distribution and/or service fees to MFD of up to 0.25% of the fund's average daily net assets to support the sale and distribution of the fund's shares, and/or shareholder servicing and account maintenance activities.

These fees are paid out of fund assets. Because these fees are an ongoing expense of the fund, they increase the cost of your investment over time and may cost you more than other types of sales charges.

The fund's Board of Trustees has determined not to implement payments of Rule 12b-1 fees under the Distribution Plan at this time. The 12b-1 fee may only be imposed when the Board of Trustees determines that it is in the best interests of shareholders to do so.

Financial Intermediary Compensation

The term "financial intermediary" refers to any broker, dealer, bank (including bank trust departments), registered investment adviser, financial planner, retirement plan administrator, third-party administrator, insurance company, and any other institution having a selling, administration, or any other similar or related agreement with MFD, MFS, or any of their affiliates. Financial intermediaries

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receive various forms of compensation in connection with the sale of shares of a fund and/or the servicing of shareholder accounts. Financial intermediaries may receive such compensation in the form of payments paid by MFD and/or one or more of its affiliates (for purposes of this section only, collectively, "MFD") from MFD's own additional resources, which may be made to the financial intermediary or its affiliate.

Certain financial intermediaries receive payments from MFD from MFD's own additional resources as incentives to market the MFS funds, to participate in MFD's promotional efforts and/or in recognition of their marketing support, administrative services, and/or transaction processing support, which may be made to the financial intermediary or its affiliate. This compensation from MFD is not reflected in the "Fees and Expenses" table in the fund's prospectus. MFD compensates financial intermediaries based on criteria established by MFD from time to time, including the distribution potential of the financial intermediary, the types of products and programs offered by the financial intermediary, eligibility for placement on the financial intermediary's preferred or recommended list, the financial and contractual terms with the financial intermediary, the level and/or type of marketing and administrative support provided by the financial intermediary, and the quality of the overall relationship with the financial intermediary. In particular, MFD normally considers the level of assets attributable to the financial intermediary, the level of redemptions by the financial intermediary, the level of access to the financial intermediary's representatives and management, the ability to educate the representatives of the financial intermediary about the MFS funds, and the number of representatives of the financial intermediary potentially utilizing the MFS funds with their clients.

MFD makes these additional payments to financial intermediaries for marketing support and administrative services with respect to fund shares sold or held through the financial intermediary's distribution network and/or through programs such as retirement programs, qualified tuition programs, fund supermarkets, fee-based advisory or wrap fee programs, bank trust programs, and insurance (e.g., individual or group annuity) programs. MFD also makes payments to certain financial intermediaries to help offset the costs associated with client account maintenance support, statement preparation, and transaction processing. To the extent permitted by SEC and Financial Industry Regulatory Authority (FINRA) rules and other applicable laws and regulations, MFD makes other payments or allows other promotional incentives or payments to financial intermediaries.

The types of payments described above are not exclusive and such payments can be significant to the financial intermediary. In addition, the compensation that financial intermediaries receive may vary by fund and/or class of shares sold and among financial intermediaries. Depending upon the arrangements in place at any particular time, financial intermediaries may have a financial incentive to recommend a particular fund or share class when a less expensive option with the same or similar characteristics is available or to recommend MFS funds instead of other funds that generate less or no compensation for the financial intermediary. Likewise, such compensation could create incentives for the financial intermediary to hold an investment longer than might be appropriate, or conversely, to make more frequent exchanges or other transactions than might be necessary.

You can find further details in the SAI about the payments made by MFD and its affiliates and the services provided by financial intermediaries. Financial intermediaries may charge you additional fees and/or commissions other than those disclosed in this prospectus. You should ask your financial intermediary for information about any payments it receives from MFD and its affiliates and any services it provides, as well as about fees and/or commissions it charges you. Financial intermediaries that sell or transact in fund shares may also act as a broker/dealer in connection with an MFS fund's purchase or sale of portfolio securities. However, the fund and MFS do not consider financial intermediaries' sales of shares of an MFS fund as a factor when choosing broker/dealers to effect portfolio transactions for the MFS funds.

Additional Information About the Purchase and Sale of Fund Shares

Shares of the fund may be created or redeemed directly from the fund only in Creation Units or multiples thereof.

Directly with the Fund. Fund shares are issued or redeemed only in large blocks of fund shares (previously defined as "Creation Units"), and the fund only transacts with financial institutions known as Authorized Participants, in accordance with procedures described in the SAI. Creation Unit transactions are conducted in exchange for the deposit or delivery of a designated basket of in-kind securities and/or cash at NAV next determined after receipt of an order in proper form. Creation Unit transactions may be made on any day that the NYSE is open for business. The fund reserves the right, but does not have the obligation, to reject any creation or redemption transaction at any time.

When creating or redeeming Creation Units, Authorized Participants are required to pay a fixed purchase or redemption transaction fee as well as any applicable additional variable charge, as described in the SAI.

An Authorized Participant may create or redeem a Creation Unit of the fund on any business day in exchange for the delivery of a designated basket of in-kind securities and/or cash. The fund may, in certain circumstances, offer creation units partially or solely for cash. Creation and redemption baskets may differ, and the fund may accept "custom baskets." More information regarding custom baskets is contained in the SAI. The prices at which creations and redemptions occur are based on the next calculation of NAV after a creation or redemption order is received in proper form under the applicable Authorized Participant Agreement. Authorized Participants may create or redeem Creation Units for their own accounts or for their customers, including, without limitation, affiliates of the fund.

The fund anticipates regularly meeting redemption requests primarily through in-kind redemptions. However, the fund reserves the right to pay redemption proceeds to an Authorized Participant entirely or partly in cash. Under normal circumstances, the fund will pay out redemption proceeds to a redeeming Authorized Participant within two business days after the Authorized Participant's redemption request is received, in accordance with the process set forth in the fund's SAI and in the agreement between the Authorized Participant and MFD. However, the fund may delay processing an Authorized Participant's redemption request for up to seven days. Under unusual circumstances, such as when the NYSE is closed, trading on the NYSE is restricted, or as permitted by the SEC, the fund may suspend redemptions or postpone payment for more than seven days. With respect to redemptions that include foreign common stock, the fund may pay out redemption proceeds or deliver the securities up to 15 days after the receipt of a redemption request.

Information about the procedures regarding creation and redemption of Creation Units (including the cut-off times for receipt of creation and redemption orders) and the applicable transaction fees and/or any variable fees is included in the fund's SAI.

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In the Secondary Market. Individual shares of the fund may be purchased and sold only on a national securities exchange through brokers. Fund shares are listed for trading on the NYSE and may be sold at a premium or discount to NAV. As a result, you may pay more than NAV when you purchase shares, and receive less than NAV when you sell shares, in the secondary market. If you buy or sell shares in the secondary market, you will generally incur customary brokerage commissions and charges and you may also incur the cost of the spread between the price at which a dealer will buy fund shares and the somewhat higher price at which a dealer will sell shares. Due to such commissions and charges and spread costs, frequent trading of the fund's shares may detract significantly from investment returns. There are various methods by which investors can purchase and sell shares and various orders that may be placed. You should consult your financial intermediary before purchasing or selling shares of the fund. The trading prices of the fund's shares in the secondary market generally differ from the fund's daily NAV per share and are affected by market forces such as supply and demand, economic conditions, and other factors. Information regarding the intraday indicative value (IIV) of the fund may be disseminated every 15 seconds throughout the trading day by the national securities exchange on which the fund's shares are primarily listed or by market data vendors or other information providers. The IIV is based on the current market value of the securities and/or cash included in the fund's IIV basket. The IIV does not necessarily reflect the precise composition of the current portfolio of securities and instruments held by the fund at a particular point in time or the best possible valuation of the current portfolio. Unlike the fund's NAV, the IIV may not reflect estimated accrued interest, dividends and other income, or fund expenses. Therefore, the IIV should not be viewed as a "real-time" update of the NAV, which is computed only once a day. The IIV is generally determined by using both current market quotations and/or price quotations obtained from broker-dealers that may trade in the portfolio securities and instruments included in the fund's IIV basket. The fund is not involved in, or responsible for, the calculation or dissemination of the IIV and makes no representation or warranty as to its accuracy. An inaccuracy in the IIV could result from various factors, including the difficulty of pricing portfolio instruments on an intraday basis.

Premium and Discount Information. Information showing the number of days the market price of the fund's shares was greater than the fund's NAV (premium) and the number of days it was less than the fund's NAV (discount) for various time periods is available at www.mfs.com. NAV is the price at which the fund issues and redeems its shares, and it is calculated in accordance with the fund's valuation policy and procedures. On the other hand, the market price is generally the official closing price of the fund's shares on an exchange. The fund's market price may be at, above (at a premium) or below (at a discount) to its NAV on days the NYSE is open for trading. The NAV of the fund will fluctuate with changes in the value of its portfolio holdings. The market price of the fund will fluctuate based on changes in the fund's NAV, as well as market supply and demand. Shareholders may pay more than NAV when they buy fund shares and less than NAV when they sell fund shares because such shares are bought and sold at current market prices. The market price is also used to calculate the market returns of the fund.

Frequent Trading. The fund's Board of Trustees has not adopted policies and procedures designed to prevent or monitor for frequent purchases and redemptions of the fund's shares because the fund sells and redeems shares at NAV only in Creation Units, pursuant to the terms of the agreement between an Authorized Participant and MFD,and such direct trading between the fund and Authorized Participants is critical to seeking to ensure that the fund's shares trade at or close to NAV. Further, the vast majority of trading in fund shares occurs on the secondary market, which does not involve the fund directly and, therefore, does not cause the fund to experience many of the harmful effects of market timing, such as dilution and disruption of portfolio management. In addition, the fund may impose a transaction fee on Creation Unit transactions, which is designed to offset transfer and other transaction costs incurred by the fund in connection with the issuance and redemption of Creation Units and may employ fair valuation pricing to minimize potential dilution from market timing. The fund reserves the right to reject any purchase order at any time and reserves the right to impose restrictions on disruptive, excessive, or short-term trading.

Other Information

Valuation

Determination of Fund Net Asset Value

The price of the fund's shares is based on its net asset value. The net asset value of the fund's shares is determined each day the NYSE is open for trading as of the close of regular trading on the NYSE (generally 4:00 p.m. Eastern time). However, net asset value may be calculated earlier in emergency situations or as otherwise permitted by the SEC. Net asset value per share is computed by dividing the net assets allocated to the fund by the number of shares outstanding for that fund. On days when the NYSE is closed (such as weekends and holidays), net asset value is not calculated, and the fund does not transact creation and redemption orders. To the extent the fund's assets are traded in other markets on days when the fund does not price its shares, the value of the fund's assets will likely change when shareholders will not be able to purchase or redeem shares of the fund.

To determine net asset value, the fund's investments for which reliable market quotations are readily available are valued at market value, and funds in which the fund invests are generally valued at their net asset value per share. Certain short term debt instruments may be valued at amortized cost.

The Board of Trustees has delegated primary responsibility for determining or causing to be determined the value of the fund's investments to MFS pursuant to the fund's valuation policy and procedures approved by the Board of Trustees. The Board of Trustees has designated MFS as the "valuation designee" of the fund. As valuation designee, MFS will determine the fair value, in good faith, of securities and other instruments held by the fund for which market quotations are not readily available and, among other things, will assess and manage material risks associated with fair value determinations, select, apply, and test fair value methodologies, and oversee and evaluate pricing services used in valuing the fund's investments. If MFS determines that reliable market quotations are not readily available, investments are valued at fair value as determined in good faith by MFS in accordance with the fair valuation policy and procedures adopted by MFS.

In addition, investments may be valued at fair value if MFS 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 a foreign exchange or market) and prior to the determination of the fund's net asset value, or after the halting 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 on a frequent basis 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

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value may be deemed to have a material effect on the value of securities traded in foreign markets. Accordingly, foreign equity securities may be valued at fair value. MFS 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.

Market Share Prices

Shares of the fund may be purchased and sold by investors in the secondary market through a financial intermediary at market price, which may vary throughout the trading day and may differ from NAV.

Distributions

The fund intends to declare and pay any dividends to shareholders at least annually.

Any capital gains are distributed at least annually.

Distribution Options

No dividend reinvestment options are offered by the fund. Dividend distributions may be reinvested automatically in additional shares only if the financial intermediary through which an investor purchased fund shares makes such option available.

Beneficial owners of fund shares should contact their financial intermediary to determine the availability and costs of a dividend reinvestment program.

Book Entry

Shares of the fund are held in book-entry form, which means that no stock certificates are issued. The Depository Trust Company (DTC), or its nominee, is the registered owner of, and holds legal title to, all outstanding shares of the fund. Your beneficial ownership of shares will be shown on the records of DTC and the DTC participant financial intermediary through which you hold the shares. As beneficial owner of shares, you are not entitled to receive physical delivery of share certificates or have shares registered in your name, and you are not considered a registered owner of fund shares. Therefore, to exercise any rights as an owner of fund shares, you must rely on the procedures of DTC and its participants.

Your financial intermediary will provide you with account statements, confirmations of your purchases and sales, and tax information. Your financial intermediary will also be responsible for distributing income and capital gain distributions and for sending you shareholder reports and other information as may be required.

Note to Authorized Participants Regarding Continuous Offering

Certain legal risks may exist that are unique to Authorized Participants purchasing Creation Units directly from the fund. Because new Creation Units may be issued on an ongoing basis, at any point a "distribution," as such term is used in the Securities Act of 1933, as amended (Securities Act), could be occurring. As a broker-dealer, certain activities that Authorized Participants perform may, depending on the circumstances, result in the Authorized Participant being deemed a participant in a distribution, in a manner which could render the Authorized Participant a statutory underwriter and subject the Authorized Participant to the prospectus delivery and liability provisions of the Securities Act.

For example, an Authorized Participant may be deemed a statutory underwriter if the Authorized Participant purchases Creation Units from the fund, breaks them down into individual fund shares, and sells such shares directly to customers, or if the Authorized Participant chooses to couple the creation of a supply of new fund shares with an active selling effort involving solicitation of secondary market demand for fund shares. A determination of whether a person is an underwriter for purposes of the Securities Act depends upon all of the facts and circumstances pertaining to that person's activities, and the examples mentioned here should not be considered a complete description of all the activities that could lead to a categorization as an underwriter.

Dealers who are not "underwriters" but are participating in a distribution (as opposed to engaging in ordinary secondary market transactions), and thus dealing with shares as part of an "unsold allotment" within the meaning of Section 4(a)(3)(C) of the Securities Act, will be unable to take advantage of the prospectus delivery exemption provided by Section 4(a)(3) of the Securities Act. This is because the prospectus delivery exemption in Section 4(a) (3) of the Securities Act is not available in respect of such transactions as a result of Section 24(d) of the Investment Company Act of 1940, as amended. As a result, financial intermediaries should note that dealers who are not underwriters but are participating in a distribution (as opposed to engaging in ordinary secondary market transactions) and thus dealing with the shares that are part of an overallotment within the meaning of Section 4(a)(3)(A) of the Securities Act would be unable to take advantage of the prospectus delivery exemption provided by Section 4(a)(3) of the Securities Act. Firms that incur a prospectus delivery obligation with respect to shares of the fund are reminded that, under Rule 153 under the Securities Act, a prospectus delivery obligation under Section 5(b) (2) of the Securities Act owed to an exchange member in connection with a sale on an exchange is satisfied by the fact that the prospectus is available at the exchange upon request. The prospectus delivery mechanism provided in Rule 153 is only available with respect to transactions on an exchange. Certain affiliates of the fund may purchase and resell fund shares pursuant to this prospectus.

Tax Considerations

The following discussion is very general. You are urged to consult your tax adviser regarding the effect that an investment in the fund will have on your particular tax situation, including possible U.S. federal, state, and local and non-U.S. taxes. This discussion does not apply to shares of the fund held through tax-advantaged accounts such as retirement plans or by shareholders that are not "United States persons" under the Internal Revenue Code of 1986, as amended (Internal Revenue Code).

The fund expects to distribute substantially all of its income and gains annually. Distributions from the fund are generally taxable to shareholders. If you buy shares when the fund has realized but not yet distributed ordinary income or capital gains, you will pay full price for the shares and then receive a portion back as a taxable distribution if you continue to hold the shares through that distribution's record date.

Any gain resulting from the redemption, sale, or exchange of your shares will generally also be subject to tax.

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For U.S. federal income tax purposes, distributions of investment income are generally taxable as ordinary income. Taxes on distributions of capital gains are determined by how long the fund owned or is deemed to have owned the investments that generated them, rather than how long you have owned your shares of the fund. Distributions of gains from the sale of investments that the fund owned for more than one year and that are properly reported by the fund as capital gain dividends will be treated as long-term capital gains includible in net capital gain and taxed to individuals at reduced rates. Distributions of gains from the sale of investments that the fund owned for one year or less will be taxable as ordinary income. If some or all of the fund's income derives from "qualified dividend income" and if you are an individual who meets holding period and other requirements with respect to the fund's shares, those distributions that are properly reported by the fund as derived from qualified dividend income are taxed to you at the reduced rates applicable to net capital gains.

A 3.8% Medicare contribution tax is generally imposed on distributions paid by the fund (other than exempt-interest dividends, if any) to, and net gains recognized on the sale, redemption, exchange, or other taxable disposition of shares of the fund by certain individuals, estates, and trusts to the extent their income exceeds certain threshold amounts.

The fund's investments in foreign securities may be subject to foreign withholding or other taxes, which will decrease the fund's return on those securities. The fund generally will be eligible to elect to "pass through" to you foreign income taxes that it pays. If the fund so elects, you must include your share of those taxes in gross income as a distribution from the fund and you will be allowed to claim a credit (or a deduction) for such amounts on your U.S. federal income tax return, subject to certain limitations. In addition, the fund's investments in certain foreign securities (including fixed income securities and derivatives) denominated in foreign currencies may increase or accelerate the fund's recognition of ordinary income and may affect the timing, amount, or character of the fund's distributions.

The IRS Form 1099 that is provided to you early each year details your distributions from the fund and how they are treated for U.S. federal tax purposes, and cost basis information for shares purchased on or after January 1, 2012, that you redeemed, sold, or exchanged. Our default method for calculating cost basis is average cost basis. More information about other cost basis methods and a cost basis selection/change form is available on mfs.com. If your account is held by your financial intermediary, you must contact your financial intermediary to obtain information about available cost basis methods and cost basis elections for your account.

Authorized Participants. An Authorized Participant that exchanges securities for Creation Units may realize a gain or loss equal to the difference between the fair market value of the Creation Units at the time of purchase and the sum of the Authorized Participant's cost basis in the securities transferred plus any cash paid.

An Authorized Participant that exchanges Creation Units for securities may realize a gain or loss equal to the difference between the Authorized Participant's cost basis in the Creation Units and the sum of the fair market value of the securities plus any cash received. The Internal Revenue Service (IRS), however, may assert that a loss realized upon an exchange of primarily securities for Creation Units cannot be deducted currently under the rules governing "wash sales," or on the basis that there has been no significant change in economic position.

Authorized Participants who are dealers in securities are subject to different tax treatment on the exchange for or redemption of Creation Units. Authorized Participants exchanging securities for Creation Units or redeeming Creation Units should consult with their own tax advisor.

Information about the Summary Prospectus, Prospectus, and SAI

The summary prospectus, prospectus, and SAI for a fund provide information concerning the fund. The summary prospectus, prospectus, and SAI are updated at least annually and any information provided in a summary prospectus, prospectus, or SAI can be changed without a shareholder vote unless specifically stated otherwise. The summary prospectus, prospectus, and SAI are not contracts between the fund and its shareholders and do not give rise to any contractual rights or obligations or any shareholder rights other than any rights conferred by federal or state securities laws that may not be waived.

Derivative Actions and Forum Selection

The trust's Declaration of Trust provides that shareholders may not bring suit on behalf of the fund without first requesting that the Board of Trustees bring such suit unless there would be irreparable injury to the fund or if a majority of the Board of Trustees (or a majority of the Board of Trustees on any committee established to consider the merits of such action) have a personal financial interest in the action. This provision of the Declaration of Trust does not apply to claims arising under federal securities laws. Trustees of the trust are not considered to have a personal financial interest by virtue of being compensated for their services as Trustees of the trust or as trustees of MFS funds with the same or an affiliated investment adviser or distributor.

Under the trust's By-Laws and Declaration of Trust, any claims asserted against or on behalf of the fund, including claims against Trustees and Officers of the trust, must be brought in state and federal courts located within the Commonwealth of Massachusetts. The designation of exclusive forum may make it more expensive for a shareholder to bring a suit and may limit a shareholder's ability to litigate a claim in a jurisdiction or forum that may be more convenient or favorable to the shareholder.

Provision of Shareholder Reports and Summary Prospectuses

The fund produces shareholder reports every six months and updates its summary prospectus and prospectus annually. To avoid sending duplicate copies of materials to households, only one paper copy of the fund's annual and semiannual shareholder 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 the fund (please see back cover for telephone number) to request that copies of these reports and summary prospectuses be sent personally to that shareholder.

Additional Information on Fees and Expenses

Fees and Expenses

The annual fund operating expenses shown in "Fees and Expenses" are based on estimated "Other Expenses" for the current fiscal year expressed as a percentage of a fund's estimated average net assets during the period.

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Financial Highlights

The fund had not commenced operations as of the date of this prospectus; therefore, no Financial Highlights are included.

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MFS Blended Research Emerging Markets Equity ETF

Shareholder Communications with the Board of Trustees.Shareholders may mail written communications to the Board of Trustees to the attention of the Board of Trustees, [fund name], Massachusetts Financial Services Company, 111 Huntington Avenue, Boston, MA 02199, Attention: Fund Secretary. Shareholder communications must (i) be in writing and be signed by the shareholder, (ii) identify the MFS fund to which they relate, and (iii) identify the number of shares held by the shareholder.

If you want more information about MFS Blended Research Emerging Markets Equity ETF, the following documents are available free upon request:

Annual/Semiannual Reports and Form N-CSR Filings.The fund's annual and semiannual shareholder reports and Form N-CSR contain information about the fund's actual investments. Annual shareholder reports discuss the effect of recent market conditions and investment strategies on the fund's performance during its last fiscal year. Form N-CSR includes the fund's annual and semiannual financial statements.

Statement of Additional Information (SAI). The SAI, dated September 30, 2025, amended March 5, 2026, as may be amended or supplemented from time to time, provides more detailed information about the fund and is incorporated into this prospectus by reference.

You can get free copies of the SAI, annual/semiannual shareholder reports, fund financial statements, and other information about the fund, including current net asset values per share, and make inquiries about the fund, by contacting:

Internet: mfs.com

Telephone: 1-800-637-5637

Reports and other information about the fund are available on the EDGAR Database on the Commission's Internet website at http://www.sec.gov, and copies of this information may be obtained, upon payment of a duplicating fee, by electronic request at the following e-mail address: [email protected].

The fund's Investment Company Act file number is 811-23953.