Fidelity Merrimack Street Trust

Before you invest, you may want to review the fund’s prospectus, which contains more information about the fund and its risks. You can find the fund’s prospectus, reports to shareholders, and other information about the fund (including the fund’s SAI) online at www.fidelity.com/funddocuments/ETFs. You can also get this information at no cost by calling 1-800-FIDELITY or by sending an e-mail request to fidfunddocuments@fidelity.com. The fund’s prospectus and SAI dated April 12, 2022 are incorporated herein by reference.

Investment Objective

The fund seeks a high level of current income.

Fee Table

The following table describes the fees and expenses that may be incurred when

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

Let’s say, hypothetically, that the annual return for shares of the fund is 5% and that your shareholder fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the

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 fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund’s performance.

Principal Investment Strategies

• Normally investing at least 80% of assets in debt securities of all types that Fidelity Management & Research Company LLC (FMR) (the Adviser) believes have positive environmental, social and governance (ESG) benefits and repurchase agreements for those securities.

• Evaluating each security in which the fund invests using both a traditional bond credit, structure and relative value analysis and a consideration of the Adviser’s judgment about the security’s ESG benefits. When assessing a security’s ESG benefits and its eligibility for purchase, the Adviser considers the following, where available: (i) the sustainability practices of the security’s issuer or sponsor, as applicable (each, an “issuer”), based on an evaluation of such issuer’s individual ESG profile; (ii) ESG factors related to the security’s underlying pool of assets; and (iii) any third-party designation as a green, sustainable or sustainability-linked bond. A security’s

positive ESG benefits can be determined under any of those three factors.

• Using the Adviser’s proprietary ESG ratings process to evaluate the current state of an issuer’s sustainability practices using a data-driven framework that includes both proprietary and third-party data, and also provide a qualitative forward-looking assessment of an issuer’s sustainability outlook provided by the Adviser’s fundamental research analysts and ESG team.

• The Adviser’s ESG ratings of issuers are derived from multiple factors, including an issuer’s environmental profile, which may include, but is not limited to, carbon and toxic emissions, water management, waste management, vulnerability to the physical impacts of climate change, and research and investment into products, services, and energies that reduce emissions and/or provide opportunities to transition to less carbon-intensive products or operations. An assessment of an issuer’s social profile includes, but is not limited to, its approach to diversity and inclusion, human capital management, data privacy, product safety and human rights. With respect to governance, the independence and diversity of an issuer’s board, its compensation practices and board oversight of critical ESG issues are considered as part of the assessment. These factors are weighted based on how material the Adviser believes each factor is to an issuer’s financial outlook, and not all factors may be applicable to all issuers. Issuers with an above average ESG rating as

determined by the Adviser are considered to have positive ESG benefits and well-managed ESG risks.

• Investing in debt securities of issuers that the Adviser believes deliver tangible environmental or social impact through core business operations. An assessment of the impact characteristics of an issuer may involve corporate engagement and an analysis of issuer alignment with the United Nations Sustainable Development Goals using qualitative analysis as well as proprietary or third-party data. For example, issuers that provide access to clean water, education, or clean energy through their core business may be considered to deliver tangible impact.

• When evaluating securitized debt securities (including mortgage-backed securities, commercial mortgage-backed securities, and other asset-backed securities), generally considering the issuer’s ESG rating along with ESG factors related to the underlying pool of assets, such as energy efficiency and environmental impact of the underlying assets; providing access to affordable housing or opportunities for first time home ownership; and compliance with fair lending laws.

• In addition to its focus on debt securities with a positive ESG benefit, analyzing the credit quality of the issuer, the issuer’s potential for success, the credit, currency, and economic risks of the security and its issuer, security-specific features, current and potential

future valuation, and trading opportunities to select investments.

• Allocating assets across investment-grade, high yield, and emerging market debt securities. Emerging markets include countries that have an emerging stock market as defined by MSCI, countries or markets with low- to middle-income economies as classified by the World Bank, and other countries or markets that the Adviser identifies as having similar emerging markets characteristics.

• Investing up to 20% of assets in lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds).

• Managing the fund to have similar overall interest rate risk to the Bloomberg MSCI U.S. Aggregate ESG Choice Bond Index.

• Investing in domestic and foreign issuers.

• Allocating assets across different asset classes, market sectors, and maturities.

• Engaging in transactions that have a leveraging effect on the fund, including investments in derivatives – such as swaps (interest rate, total return, and credit default), options, and futures contracts – and forward-settling securities, to adjust the fund’s risk exposure.

• Employing sustainable investing exclusion criteria to avoid investments in issuers that are directly engaged in, and/or derive significant revenue from,

certain industries. Please see “Fund Basics – Investment Details – Sustainable Investing Exclusions” for additional information.

Principal Investment Risks

• Sustainability Risk. Application of FMR’s ESG ratings process and/or its sustainable investing exclusion criteria may affect the fund’s exposure to certain issuers, sectors, regions, and countries and may affect the fund’s performance depending on whether certain investments are in or out of favor. The criteria related to the fund’s ESG ratings process and/or adherence to its sustainable investing exclusion criteria may result in the fund forgoing opportunities to buy certain securities when it might otherwise be advantageous to do so, or selling securities for ESG reasons when it might be otherwise disadvantageous for it to do so. As a result, the fund’s performance may at times be better or worse than the performance of funds that do not use ESG or sustainability criteria. There are significant differences in interpretations of what it means for an issuer to have positive ESG factors. While the Adviser believes its definitions are reasonable, the portfolio decisions it makes may differ with other investors’ or advisers’ views. When evaluating an issuer, the Adviser is dependent on information or data obtained through voluntary or third-party reporting that may be incomplete, inaccurate, or unavailable, which could cause the Adviser to

incorrectly assess an issuer’s business practices.

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

• Foreign Exposure. Foreign markets, particularly emerging markets, can be more volatile than the U.S. market due to increased risks of adverse issuer, political, regulatory, market, or economic developments and can perform differently from the U.S. market. Foreign exchange rates also can be extremely volatile.

• Prepayment. The ability of an issuer of a debt security to repay principal prior to a security’s maturity can cause greater price volatility if interest rates change.

• Issuer-Specific Changes. The value of an individual security or particular type of security can be more volatile than, and can perform differently from, the market as a whole. A decline in the credit quality of an issuer or a provider of credit support or a maturity-shortening structure for a security can cause the price of a security to decrease. Lower-quality debt securities (those of less than investment-grade quality, also referred to as high yield debt securities or junk bonds) and certain types of other securities involve greater risk of default or price changes due to changes in the credit quality of the issuer. The value of lower-quality debt securities and certain types of other securities can be more volatile due to increased sensitivity to adverse issuer,

political, regulatory, market, or economic developments and can be difficult to resell.

• Fluctuation of Net Asset Value and Share Price. The net asset value per share (NAV) 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 creations and redemptions, the existence of extreme market volatility or potential 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. Given the nature of the relevant markets for certain of the fund’s securities, shares may trade at a larger premium or discount to the NAV than shares of other ETFs. In addition, in stressed market conditions or periods of market disruption or volatility, the market for shares may become less liquid in response to deteriorating liquidity in the markets for the fund’s underlying portfolio holdings.

• Trading Issues. There can be no assurance that an active trading market will be maintained. Market makers and Authorized Participants are not obligated to make a market in the fund’s shares or to submit purchase and redemption orders for creation units. In addition, trading may be halted, for example, due to market conditions.

• Leverage Risk. Leverage can increase market exposure, magnify

investment risks, and cause losses to be realized more quickly.

• Cash Transactions Risk. Unlike certain ETFs, 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.

An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Unlike individual debt securities, which typically pay principal at maturity, the value of an investment in the fund will fluctuate. You could lose money by investing in the fund.

Performance

Performance history will be available for the fund after the fund has been in operation for one calendar year.

Investment Adviser

FMR (the Adviser) is the fund’s manager. FMR Investment Management (UK) Limited (FMR UK) and other investment advisers serve as sub-advisers for the fund.

Portfolio Manager(s)

Celso Munoz (co-manager) has managed the fund since April 2022.

Ford O’Neil (co-manager) has managed the fund since April 2022.

Franco Castagliuolo (co-manager) has managed the fund since April 2022.

Michael Cheng (co-manager) has managed the fund since April 2022.

Michael Foggin (co-manager) has managed the fund since April 2022.

Michael Plage (co-manager) has managed the fund since April 2022.

Purchase and Sale of Shares

Shares of the fund are listed and traded on an exchange, and individual fund shares may only be bought and sold in the secondary market through a broker or dealer at market price. These transactions, which do not involve the fund, are made at market prices that may vary throughout the day, rather than at NAV. Shares of the fund may trade at a price greater than the fund’s NAV (premium) or less than the fund’s NAV (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.fidelity.com.

Tax Information

Distributions you receive from the fund are subject to federal income tax and generally will be taxed as ordinary income or capital gains, and may also be subject to state or local taxes, unless you are investing through a tax-advantaged retirement account (in which case you may be taxed later, upon withdrawal of your investment from such account).

Payments to Broker-Dealers and Other Financial Intermediaries

The fund, the Adviser, Fidelity Distributors Company LLC (FDC), and/or their affiliates may pay intermediaries, which may include banks, broker-dealers, retirement plan sponsors, administrators, or service-providers (who may be affiliated with the Adviser or FDC), for the sale of fund shares and related services. These payments may create a conflict of interest by influencing your intermediary and your investment professional to recommend the fund over another investment. Ask your investment professional or visit your intermediary’s web site for more information.

Fidelity Distributors Company LLC (FDC) is a member of the Securities Investor Protection Corporation (SIPC). You may obtain information about SIPC, including the SIPC brochure, by visiting www.sipc.org or calling SIPC at 202-371-8300.

Any third-party marks that may appear above are the marks of their respective owners.


Shareholder fees

(fees paid directly from your investment)			None

Annual Operating Expenses

(expenses that you pay each year as a % of the value of your investment)

Management fee			0.36%

Distribution and/or Service (12b-1) fees			None

Other expenses^(a)			0.00%


Total annual operating expenses			0.36%



1 year	$	37

3 years	$	116


1.9904945.100		CPB-SUM-0422