BlackRock Flexible Income ETF

The Securities and Exchange Commission (“SEC”) and the Commodity Futures Trading Commission have not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

BlackRock^® is a registered trademark of BlackRock Fund Advisors and its affiliates.

Ticker: BINC Stock Exchange: NYSE Arca

Investment Objectives

The BlackRock Flexible Income ETF (the “Fund”) seeks to maximize long-term income by primarily investing in debt and income-producing securities with a secondary objective of capital appreciation.

Fees and Expenses

The following table describes the fees and expenses that you will incur if you buy, hold and sell shares of the Fund. The investment advisory agreement between BlackRock ETF Trust II (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except (i) the management fees, (ii) interest expenses, (iii) taxes, (iv) expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, (v) distribution fees or expenses, and (vi) litigation expenses and any extraordinary expenses. The Fund may incur “Acquired Fund Fees and Expenses.” Acquired Fund Fees and Expenses reflect the Fund’s pro rata share of the fees and expenses incurred indirectly by the Fund as a result of investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund.

You may also incur usual and customary brokerage commissions and other charges when buying or selling shares of the Fund, which are not reflected in the Example that follows:

Annual Fund Operating Expenses
(ongoing expenses that you pay each year as a
percentage of the value of your investments)

Management
Fees^1,2

Distribution
and
Service (12b-1)
Fees

Other
Expenses

Acquired
Fund
Fees and
Expenses^1,3

Total Annual
Fund
Operating
Expenses³

Fee
Waiver^1,2

Total Annual
Fund
Operating
Expenses
After Fee Waiver^1,2

0.50%

None

0.03%

0.53%

(0.13)%

0.40%

As described in the “Management” section of the Fund’s prospectus beginning on page 23, BFA has contractually agreed to waive a portion of its management fees in an amount equal to the aggregate Acquired Fund Fees and Expenses, if any, attributable to investments by the Fund in other funds advised by BFA or its affiliates through June 30, 2025. The agreement may be terminated upon 90 days’ notice by a majority of the non-interested trustees of the Trust or by a vote of a majority of the outstanding voting securities of the Fund.

As described in the “Management” section of the Fund’s prospectus beginning on page 23, BFA has contractually agreed to waive 0.10% of its management fee payable, through June 30, 2025.

The Total Annual Fund Operating Expenses do not correlate to the ratios of expenses to average net assets given in the Fund’s most recent annual report, which do not include Acquired Fund Fees and Expenses.

Example. This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:


1 Year		3 Years
$41		$157

Portfolio Turnover. The Fund may pay 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 the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 54% of the average value of its portfolio.

Principal Investment Strategies

Under normal market conditions, the Fund will invest in a combination of fixed-income securities, including, but not limited to: high yield securities; obligations issued or guaranteed by the U.S. Government, its agencies or instrumentalities; mortgage-backed securities issued or guaranteed by the U.S. Government or its agencies or instrumentalities, including U.S. agency mortgage pass-through securities; commercial mortgage-backed securities (“CMBS”); non-agency residential mortgage-backed securities; mortgage to-be-announced (“TBA”) securities; municipal securities; securitized assets such as asset-backed securities; dollar-denominated and non-dollar-denominated debt obligations of U.S. or foreign issuers, including emerging market issuers; and money market securities. Depending on market conditions, the Fund may invest in other market sectors. The Fund may also gain exposure to fixed-income securities through its investments in affiliated investment companies, including other exchange-traded funds, that invest in such securities. The Fund may invest more than 10% of its total assets in such affiliated investment companies.

The Fund may invest up to 20% of its assets in U.S.-domiciled, U.S.-registered dollar-denominated investment grade corporate bonds, U.S. Treasury securities, U.S. agency securities and U.S. agency mortgage-backed securities. The Fund may invest without limit in securities rated below investment grade or which are deemed to be of comparable quality by Fund management (“high yield” or “junk” bonds) at the time of purchase. Fund management considers split rated bonds (bonds that receive different ratings from two or more rating agencies) to have the lower credit rating.

The Fund may invest in bonds of any maturity or duration. The Fund maintains an average portfolio duration that is between 1 and 5 years.

The Fund may invest up to 10% of its assets in preferred securities. The Fund may invest in collateralized debt obligations (“CDOs”), including up to 15% of its assets in collateralized loan obligations (“CLOs”). CDOs are types of asset-backed securities. CLOs are ordinarily issued by a trust or other special purpose entity and are typically collateralized by a pool of loans, which may include, among others, domestic and non-U.S. senior secured loans, senior unsecured loans, and subordinate corporate loans, including loans that may be rated below investment grade or equivalent unrated loans, held by such issuer. The Fund may also invest up to 15% of its

assets in floating rate loans. The Fund may invest in other types of floating rate instruments without limit.

The Fund may use derivatives, such as futures contracts, options (including, but not limited to, options on futures and swaps) and various other instruments including, but not limited to, interest rate, total return, credit default and credit default index swaps (which can be used to transfer the credit risk of a security without actually transferring ownership of the security or to customize exposure to a particular credit risk) and indexed and inverse floating-rate securities. The Fund may also invest in derivatives based on foreign currencies. In addition, the Fund may use derivatives and short sales to enhance returns as part of an overall investment strategy or to offset a potential decline in the value of other holdings (commonly referred to as a “hedge”), although the Fund is not required to hedge and may choose not to do so.

The Fund is classified as non-diversified under the Investment Company Act.

The Fund may engage in active and frequent trading of portfolio securities to achieve its primary investment strategies.

Summary of Principal Risks

As with any investment, you could lose all or part of your investment in the Fund, and the Fund’s performance could trail that of other investments. The Fund is subject to certain risks, including the principal risks noted below, any of which may adversely affect the Fund’s net asset value per share (“NAV”), trading price, yield, total return and ability to meet its investment objectives. Unlike many exchange-traded funds (“ETFs”), the Fund is not an index-based ETF. The relative significance of each risk factor below may change over time and you should review each risk factor carefully.

negative yield. A low or negative yield would cause the Fund to lose money in certain conditions and over certain time periods. An increase in interest rates will generally cause the value of securities held by the Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain fixed-income investments, including those held by the Fund. Because rates on certain floating rate debt securities typically reset only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate debt securities. The historically low interest rate environment in recent years heightens the risks associated with rising interest rates.

Income Risk. Income risk is the risk that the Fund’s yield will vary as short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates.

Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer’s or counterparty’s financial condition and on the terms of an obligation.

Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund may “call” or repay the security before its stated maturity, and the Fund may have to reinvest the proceeds in securities with lower yields, which would result in a decline in the Fund’s income, or in securities with greater risks or with other less favorable features.

Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s income and potentially in the value of the Fund’s investments.

Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential.

High Yield Securities Risk. Securities that are rated below investment-grade (commonly referred to as “junk bonds,” which may include those bonds rated below (“BBB-” by S&P Global Ratings and Fitch, Inc. (“Fitch”), “Baa3” by Moody’s Investors Service, Inc. (“Moody’s”), or are unrated, may be deemed speculative, may involve greater levels of risk than higher-rated securities of similar maturity and may be more likely to default.

Asset-Backed and Mortgage-Backed Securities Risk. Asset-backed securities (“ABS”) and mortgage-backed securities (“MBS”) (residential and commercial) represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. ABS and MBS are subject to credit, interest rate, call, extension, valuation and liquidity risk. These securities, in most cases, are not backed by the full faith and credit of the U.S. government and are subject to the risk of default on the underlying asset or mortgage, particularly during periods of economic downturn. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain ABS and MBS.

U.S. Agency Debt Risk. The Fund invests in unsecured bonds or debentures issued or guaranteed by the U.S. government or one of its agencies or sponsored entities. Certain debt issuances by U.S. government agencies or sponsored entities, including, among others, Fannie Mae, Freddie Mac, the Federal Home Loan Banks (“FHLB”), and the Tennessee Valley Authority (“TVA”), are backed only by the general creditworthiness and reputation of the U.S. government agency or sponsored entity and not the full faith and credit of the U.S. government and, as a result, are subject to additional credit risk. To the extent that the U.S. government has provided support to a U.S. agency or sponsored entity in the past, there can be no assurance that the U.S. government will provide support in the future if it is not obligated to do so. Ginnie Mae securities and

certain foreign government debt issuances guaranteed by the U.S. government are backed by the full faith and credit of the U.S. government.

U.S. Agency Mortgage-Backed Securities Risk. The Fund invests in MBS issued or guaranteed by the U.S. government or one of its agencies or sponsored entities, some of which may not be backed by the full faith and credit of the U.S. government. MBS represent interests in “pools” of mortgages and are subject to interest rate, prepayment, and extension risk. MBS react differently to changes in interest rates than other bonds, and the prices of MBS may reflect adverse economic and market conditions. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain MBS. MBS are also subject to the risk of default on the underlying mortgage loans, particularly during periods of economic downturn. Default or bankruptcy of a counterparty to a TBA transaction would expose the Fund to possible losses.

Commercial Mortgage-Backed Securities Risk. CMBS are not backed by the full faith and credit of the U.S. government and are subject to risk of default on the underlying mortgages, particularly during periods of economic downturn. CMBS issued by non-government entities may offer higher yields than those issued by government entities, but also may be subject to greater volatility than government issues. CMBS are subject to a greater degree of prepayment and extension risk than many other forms of fixed-income securities and therefore react differently to changes in interest rates than other bonds, and the prices of CMBS may reflect adverse economic and market conditions.

Collateralized Debt Obligations Risk. In addition to the typical risks associated with fixed-income securities and asset-backed securities, CDOs, including CLOs, carry additional risks including, but not limited to: (i) the possibility that distributions from collateral securities will not be adequate to make

interest or other payments; (ii) the risk that the collateral may default or decline in value or be downgraded, if rated by a nationally recognized statistical rating organization; (iii) the Fund may invest in tranches of CDOs that are subordinate to other tranches; (iv) the structure and complexity of the transaction and the legal documents could lead to disputes among investors regarding the characterization of proceeds; (v) the investment return achieved by the Fund could be significantly different than those predicted by financial models; (vi) the lack of a readily available secondary market for CDOs; (vii) the risk of forced “fire sale” liquidation due to technical defaults such as coverage test failures; and (viii) the CDO’s manager may perform poorly.

Municipal Securities Risk. Municipal securities can be significantly affected by political or economic changes, including changes made in the law after issuance of the securities, as well as uncertainties in the municipal market related to taxation, legislative changes or the rights of municipal security holders, including in connection with an issuer insolvency. Municipal securities backed by current or anticipated revenues from a specific project or specific assets can be negatively affected by the inability to collect revenues from such projects or assets. Certain municipal securities are issued by entities with limited taxing authority such as school districts, or are dependent on revenue from a particular sector or industry, such as the utilities sector, infrastructure sector, or transportation industry. In the event of a default or insolvency, certain issuers of municipal bonds may be subject to proceedings other than those specified by U.S. bankruptcy laws, which may impact the Fund’s ability to ultimately recover assets.

needs, the Fund may hold additional cash, sell investments or temporarily borrow from banks and other lenders.

Asset Class Risk. Securities and other assets in the Fund’s portfolio may underperform in comparison to the general financial markets, a particular financial market or other asset classes.

Assets Under Management (AUM) Risk. From time to time, an Authorized Participant (as defined in the Creations and Redemptions section of this prospectus (the “Prospectus”) a third-party investor, the Fund’s adviser or an affiliate of the Fund’s adviser, or a fund may invest in the Fund and hold its investment for a specific period of time in order to facilitate commencement of the Fund’s operations or to allow the Fund to achieve size or scale. There can be no assurance that any such entity would not redeem its investment or that the size of the Fund would be maintained at such levels, which could negatively impact the Fund.

Authorized Participant Concentration Risk. Only an Authorized Participant (as defined in the Creations and Redemptions section of this Prospectus) may engage in creation or redemption transactions directly with the Fund, and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem, Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant Concentration Risk may be heightened for ETFs, such as the Fund, that invest in securities issued by non-U.S. issuers or other securities or instruments that have lower trading volumes.

Cybersecurity Risk. Failures or breaches of the electronic systems of the Fund, the Fund’s adviser, distributor, and other service providers (including the benchmark provider), market makers, Authorized Participants or the issuers of securities in which the Fund invests have the ability to cause disruptions, negatively impact the Fund’s business operations and/or potentially result in financial losses to the Fund and its shareholders. While the Fund has established business continuity plans and risk management systems seeking to address system

breaches or failures, there are inherent limitations in such plans and systems. Furthermore, the Fund cannot control the cybersecurity plans and systems of the Fund’s service providers, market makers, Authorized Participants or issuers of securities in which the Fund invests.

Forward Foreign Currency Exchange Contracts. Forward foreign currency exchange transactions are over-the-counter (“OTC”) contracts to purchase or sell a specified amount of a specified currency or multinational currency unit at a price and future date set at the time of the contract. Forward foreign currency exchange contracts do not eliminate fluctuations in the value of non-U.S. securities but rather allow the Fund to establish a fixed rate of exchange for a future point in time. This strategy can have the effect of reducing returns and minimizing opportunities for gain.

Futures Contract Risk. Futures are standardized, exchange-traded contracts that obligate a purchaser to take delivery, and a seller to make delivery, of a specific amount of an asset at a specified future date at a specified price. Unlike equities, which typically entitle the holder to a continuing ownership stake in an issuer, futures contracts normally specify a certain date for settlement in cash based on the level of the reference rate. The primary risks associated with the use of futures contracts, or swaps or other derivatives referencing futures contracts, are: (i) the imperfect correlation between the change in market value of the instruments or swaps or other derivatives referencing futures contracts held by the Fund and the price of the futures contract; (ii) possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; (iii) losses caused by unanticipated market movements, which are potentially unlimited; (iv) BFA’s inability to predict correctly the direction of prices and other economic factors; and (v) the possibility that the counterparty will default in the performance of its obligations.

High Portfolio Turnover Risk. The Fund may engage in active and frequent trading of its portfolio securities or other assets. High portfolio turnover (considered by the Fund to mean higher than 100% annually) may result in increased transaction costs to the Fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of the securities or other assets and on reinvestment in other securities, as well as possible increased taxable distributions.

Illiquid Investments Risk. The Fund may not acquire any illiquid investment if, immediately after

the acquisition, the Fund would have invested more than 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. In addition, if the Fund is limited in its ability to sell illiquid investments during periods when shareholders are redeeming their shares, the Fund will need to sell liquid securities to meet redemption requests and illiquid securities will become a larger portion of the Fund’s holdings. During periods of market volatility, liquidity in the market for the Fund’s shares may be impacted by the liquidity in the market for the underlying securities or instruments held by the Fund, which could lead to the Fund’s shares trading at a premium or discount to the Fund’s NAV.

Infectious Illness Risk. A widespread outbreak of an infectious illness, such as the COVID-19 pandemic, may result in travel restrictions, disruption of healthcare services, prolonged quarantines, cancellations, supply chain disruptions, business closures, lower consumer demand, layoffs, ratings downgrades, defaults and other significant economic, social and political impacts. Markets may experience temporary closures, extreme volatility, severe losses, reduced liquidity and increased trading costs. Such events may adversely affect the Fund and its investments and may impact the Fund’s ability to purchase or sell securities or cause elevated tracking error and increased premiums or discounts to the Fund’s NAV. Despite the development of vaccines, the duration of the COVID-19 pandemic and its effects cannot be predicted with certainty.

Investment Companies and ETFs Risk. Subject to the limitations set forth in the Investment Company Act and the rules thereunder, the Fund may acquire shares in other investment companies and in ETFs, some of which may be affiliated investment companies. The market value of the shares of other investment companies and ETFs may differ from their net asset value. As an investor in investment companies and ETFs, the Fund would bear its ratable share of that entity’s expenses, including its investment advisory and administration fees, while continuing to pay its own advisory and administration fees and other expenses (to the extent not offset by BFA through waivers). As a result, shareholders will be absorbing duplicate levels of fees with respect to

investments in other investment companies and ETFs (to the extent not offset by BFA through waivers).

Management Risk. The Fund is subject to management risk, which is the risk that the investment process, techniques and analyses applied by BFA will not produce the desired results, and those securities or other financial instruments selected by BFA may result in returns that are inconsistent with the Fund’s investment objective. In addition, legislative, regulatory, or tax developments may affect the investment techniques available to BFA in connection with managing the Fund and may also adversely affect the ability of the Fund to achieve its investment objective.

Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. Local, regional or global events such as war, acts of terrorism, public health issues, recessions, the prospect or occurrence of a sovereign default or other financial crisis, or other events could have a significant impact on the Fund and its investments and could result in increased premiums or discounts to the Fund’s NAV.

Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. Unlike some ETFs that track specific indexes, the Fund does not seek to replicate the performance of a specified index. Index-based ETFs have generally traded at prices that closely correspond to NAV per share. Given the high level of transparency of the Fund’s holdings, BFA believes that the trading experience of the Fund should be similar to that of index-based ETFs. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund’s shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND’S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Money Market Instruments Risk. The value of money market instruments may be affected by changing interest rates and by changes in the credit ratings of the investments. If a significant amount of the Fund’s assets are invested in money market instruments, it will be more difficult for the Fund to achieve its investment objective. An investment in a money market fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (“FDIC”) or any other government agency. It is possible to lose money by investing in a money market fund. Money market funds other than government money market funds or retail money market funds “float” their NAV instead of using a stable $1.00 per share price.

Non-Diversification Risk. To the extent the Fund is non-diversified, the Fund may invest a Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund’s performance may be adversely affected and the Fund may be more susceptible to the risks associated with these particular issuers or to a single economic, political or regulatory occurrence affecting these issuers.

Options. An option is an agreement that, for a premium payment or fee, gives the option holder (the purchaser) the right but not the obligation to buy (a “call option”) or sell (a “put option”) the underlying asset (or settle for cash in an amount based on an underlying asset, rate, or index) at a specified price (the “exercise price”) during a period of time or on a specified date. Investments in options are considered speculative. When the Fund purchases an option, it may lose the total premium paid for it if the price of the underlying security or other assets decreased, remained the same or failed to increase to a level at or beyond the exercise price (in the case of a call option) or increased, remained the same or failed to decrease to a level at or below the exercise price (in the case of a put option). If a put or call option purchased by the Fund were permitted to expire without being sold or exercised, its premium would represent a loss to the Fund. To the extent that the Fund writes or sells an option, if the decline or increase in the underlying asset is significantly below or above the exercise price of the written option, the Fund could experience a substantial loss.

Non-U.S. Issuers Risk. Securities issued by non-U.S. issuers carry different risks from securities issued by U.S. issuers. These risks include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations, political instability, regulatory and economic differences, and potential restrictions on the flow of international capital.

Preferred Securities Risk. Preferred securities may pay fixed or adjustable rates of return. Preferred securities are subject to issuer-specific and market risks applicable generally to equity securities. In addition, a company’s preferred securities generally pay dividends only after the company makes required payments to holders of its bonds and other debt. For this reason, the value of preferred securities will usually react more strongly than bonds and other debt to actual or perceived changes in the company’s financial condition or prospects. Preferred securities of smaller companies may be more vulnerable to adverse developments than preferred securities of larger companies.

Risk of Investing in Emerging Markets. Investments in emerging market issuers may be subject to a greater risk of loss than investments in issuers located or operating in more developed markets. Emerging markets may be more likely to experience inflation, social instability, political turmoil or rapid changes in economic conditions than more

developed markets. Companies in many emerging markets are not subject to the same degree of regulatory requirements, accounting standards or auditor oversight as companies in more developed countries, and as a result, information about the securities in which the Fund invests may be less reliable or complete. Emerging markets often have less reliable securities valuations and greater risk associated with custody of securities than developed markets. There may be significant obstacles to obtaining information necessary for investigations into or litigation against companies and shareholders may have limited legal remedies.

Risk of Investing in the U.S. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure.

Risk of Swap Agreements. A swap is a two-party contract that generally obligates each counterparty to exchange periodic payments based on a pre-determined underlying investment or notional amount and to exchange collateral to secure the obligations of each counterparty. Swaps may be leveraged and are subject to counterparty risk, credit risk and pricing risk. Swaps may be subject to illiquidity risk, and it may not be possible for the Fund to liquidate a swap position at an advantageous time or price, which may result in significant losses. Certain standardized interest rate and credit default swaps are required to be traded on an exchange or trading platform and centrally cleared. Most other swaps are entered into a negotiated, bi-lateral basis and traded in the over-the counter market. Swaps are subject to bi-lateral variation margin. The Fund is required by financial regulators to post initial margin in connection with trading over-the-counter swaps. These requirements may raise the costs for the Fund’s investment in swaps.

Small Fund Risk. When the Fund’s size is small, the Fund may experience low trading volume and wide bid/ask spreads. In addition, the Fund may face the risk of being delisted if the Fund does not meet certain conditions of the listing exchange. Any resulting liquidation of the Fund could cause the Fund to incur elevated transaction costs for the Fund and negative tax consequences for its shareholders.

Sovereign and Quasi-Sovereign Obligations Risk. The Fund may invest in securities issued by or guaranteed by non-U.S. sovereign governments and by entities affiliated with or backed by non-U.S. sovereign governments, which may be unable or

unwilling to repay principal or interest when due. In times of economic uncertainty, the prices of these securities may be more volatile than those of other corporate debt obligations or of other government debt obligations.

Valuation Risk. The price the Fund could receive upon the sale of a security or other asset may differ from the Fund’s valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology as a result of trade suspensions or for other reasons. Because non-U.S. exchanges may be open on days or during time periods when the Fund does not price its shares, the value of the securities or other assets in the Fund’s portfolio may change on days or during time periods when shareholders will not be able to purchase or sell the Fund’s shares.

Authorized Participants who purchase or redeem Fund shares on days when the Fund is holding fair-valued securities may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the Fund not fair-valued the securities or used a different valuation methodology. The Fund’s ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.

Performance Information

As of the date of this Prospectus, the Fund has been in operation for less than one full calendar year and therefore does not report its performance information. The Fund’s benchmark is the Bloomberg U.S. Universal Index.

Management

Portfolio Managers. Rick Rieder, Samir Lakhani, Dylan Price, Jacob Caplain and Charlotte Widjaja (the “Portfolio Managers”) are jointly and primarily responsible for the day-to-day management of the Fund. Messrs. Rieder, Lakhani, Price, Caplain and Ms. Widjaja have been Portfolio Managers of the Fund since 2023.

Purchase and Sale of Fund Shares

The Fund is an ETF. Individual shares of the Fund may only be bought and sold in the secondary market through a broker-dealer. Because ETF shares trade at market prices rather than at NAV, shares may trade at a price greater than NAV (a premium) or less than NAV (a discount). An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”).

Tax Information

The Fund intends to make distributions that may be taxable to your as ordinary income or capital gains, unless you are investing through a tax-deferred arrangement such as a 401(k) plan or an individual retirement account (“IRA”), in which case, your distributions generally will be taxable when withdrawn.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer or other financial intermediary (such as a bank), BFA or other related companies may pay the intermediary for marketing activities and presentations, educational training programs, conferences, the development of technology platforms and reporting systems or other services related to the sale or promotion of the Fund. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

This Prospectus contains important information about investing in BlackRock Flexible Income ETF (the “Fund”). Please read this Prospectus carefully before you make any investment decisions. Additional information regarding the Fund is available at www.blackrock.com.

The Fund is an actively managed ETF and, thus, does not seek to replicate the performance of a specified index. Accordingly, the management team has discretion on a daily basis to manage the Fund’s portfolio in accordance with the Fund’s investment objectives.

ETFs are funds that trade like other publicly-traded securities. Similar to shares of a mutual fund, each share of the Fund represents an ownership interest in an underlying portfolio of securities and other instruments. Unlike shares of a mutual fund, which can be bought and redeemed from the issuing fund by all shareholders at a price based on NAV, shares of the Fund may be purchased or redeemed directly from the Fund at NAV solely by Authorized Participants and only in aggregations of a specified number of shares (“Creation Units”). Also unlike shares of a mutual fund, shares of the Fund are listed on a national securities exchange and trade in the secondary market at market prices that change throughout the day.

The Fund is classified as “non-diversified” under the Investment Company Act of 1940, as amended (the “1940 Act”).

The Fund’s investment objective is a non-fundamental policy and may be changed without shareholder approval.

The Fund may invest without limit in securities rated below investment grade or which are deemed to be of comparable quality by Fund management (“high yield” or “junk” bonds) at the time of purchase. Fund management considers split rated bonds (bonds that receive different ratings from two or more rating agencies) to have the lower credit rating. The Fund may invest in bonds of any maturity or duration. The Fund maintains an average portfolio duration that is between 1 and 5 years. Duration is a measure of the price sensitivity of a debt security or portfolio of debt securities to relative changes in interest rates. For example, if interest rates increase by 1%, assuming a current portfolio duration of 5 years, and all other factors being equal, the value of the Fund’s investments would be expected to decrease by 5%.

The Fund may also invest up to 10% of its assets in preferred securities. The Fund may invest in collateralized debt obligations (“CDOs”), including up to 15% of its assets in collateralized loan obligations (“CLOs”). CDOs are types of asset-backed securities. CLOs are ordinarily issued by a trust or other special purpose entity and are typically collateralized by a pool of loans, which may include, among others, domestic and non-U.S. senior secured loans, senior unsecured loans, and subordinate corporate loans, including loans that may be rated below investment grade or equivalent unrated loans, held by such issuer. The Fund may also invest up to 15% of its assets in floating rate loans. The Fund may invest in other types of floating rate instruments without limit.

Fund may also invest in derivatives based on foreign currencies. In addition, the Fund may use derivatives and short sales to enhance returns as part of an overall investment strategy or to offset a potential decline in the value of other holdings (commonly referred to as a “hedge”), although the Fund is not required to hedge and may choose not to do so.

The Fund may engage in active and frequent trading of portfolio securities to achieve its primary investment strategies.

Investment Process. The Fund generally invests in a portfolio of fixed-income securities of varying maturities, such as corporate bonds and notes, mortgage-backed and asset-backed securities, preferred securities and government debt obligations. The Fund is not managed to a benchmark, which provides the Portfolio Managers with flexibility to allocate to and rotate across any sector in the fixed income universe. The Fund has the ability to flexibly manage duration risk by shifting between 1 to 5 years in average portfolio duration. The portfolio managers can institute hedging on a macro level to manage the overall portfolio risk from a duration and credit risk perspective, when appropriate.

Other Strategies. In addition to the principal strategies discussed above, the Fund may also invest or engage in the following investments/strategies:

The Fund is subject to various risks, including the principal risks noted below, any of which may adversely affect the Fund’s NAV, trading price, yield, total return and ability to meet its investment objectives. You could lose all or part of your investment in the Fund, and the Fund could underperform other investments. The order of the below risk factors does not indicate the significance of any particular risk factor. The Fund discloses its portfolio holdings daily at www.BlackRock.com.

Interest Rate Risk. During periods of very low or negative interest rates, the Fund may be unable to maintain positive returns or pay dividends to Fund shareholders. Very low or negative interest rates may magnify interest rate risk. Changing interest rates, including rates that fall below zero, may have unpredictable effects on markets, result in heightened market volatility and detract from the Fund’s performance to the extent the Fund is exposed to such interest rates. Additionally, under certain market conditions in which interest rates are low and the market prices for portfolio securities have increased, the Fund may have a very low or even negative yield. A low or negative yield would cause the Fund to lose money in certain conditions and over certain time periods. An increase in interest rates will generally cause the value of securities held by the Fund to decline, may lead to heightened volatility in the fixed-income markets and may adversely affect the liquidity of certain investments, including those held by the Fund. Because rates on certain floating rate debt securities typically reset only periodically, changes in prevailing interest rates (and particularly sudden and significant changes) can be expected to cause some fluctuations in the net asset value of the Fund to the extent that it invests in floating rate debt securities. The historically low interest rate environment in recent years heightens the risks associated with rising interest rates.

Income Risk. The Fund’s income may decline if interest rates fall. This decline in income can occur because the Fund may subsequently invest in lower-yielding securities as securities in its portfolio mature, (are near maturity or are called,) or the Fund otherwise needs to purchase additional securities.

Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential. Also, if a security subject to prepayment had been purchased at a premium, the value of the premium would be lost in the event of prepayment.

High Yield Securities Risk. Securities that are rated below investment-grade (commonly referred to as “junk bonds,” which may include those bonds rated below “BBB-” by S&P Global Ratings and Fitch, or below “Baa3” by Moody’s, or are unrated, may be deemed speculative, may involve greater levels of risk than higher-rated securities of similar maturity and may be more likely to default. BBB-rated bonds, although investment-grade, may share some of the same speculative characteristics as “junk bonds.”

Asset-Backed and Mortgage-Backed Securities Risk. Asset-Backed Securities (“ABS”) and Mortgage-Backed Securities (“MBS”) (residential and commercial) represent interests in “pools” of mortgages or other assets, including consumer loans or receivables held in trust. Although ABS generally experience less prepayment risk than residential mortgage-backed securities, MBS and ABS, like traditional fixed-income securities, are subject to credit, interest rate, call, extension, valuation and liquidity risk. Because of call and extension risk, ABS and MBS react differently to changes in interest rates than other bonds. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain ABS and MBS.

ABS and MBS may not be backed by the full faith and credit of the U.S. government and are subject to risk of default on the underlying mortgage or asset, particularly during periods of economic downturn.

MBS may be either pass-through securities or Collateralized Mortgage Obligations (“CMOs”). Pass-through securities represent a right to receive principal and interest payments collected on a pool of mortgages, which are passed through to security holders. CMOs are created by dividing the principal and interest payments collected on a pool of mortgages into several revenue streams (tranches) with different priority rights to portions of the underlying mortgage payments. Certain CMO tranches may represent a right to receive interest only, principal only or an amount that remains after floating-rate tranches are paid (an inverse floater). These securities are frequently referred to as “mortgage derivatives” and may be extremely sensitive to changes in interest rates. Interest rates on inverse floaters, for example, vary inversely with a short-term floating rate (which may be reset periodically). Interest rates on inverse floaters will decrease when short-term rates increase, and will increase when short-term rates decrease. These securities have the effect of providing a degree of investment leverage. In response to changes in market interest rates or other market conditions, the value of an inverse floater may increase or decrease at a multiple of the increase or decrease in the value of the underlying securities. If the Fund invests in CMO tranches (including CMO tranches issued by government agencies) and interest rates move in a manner not anticipated by Fund management, it is possible that the Fund could lose all or substantially all of its investment.

In response to the financial crisis that began in 2008, the Federal Reserve System (the “Fed”) attempted to keep mortgage rates low by acting as a buyer of mortgage-backed assets. This support has ended. As a result, mortgage rates may rise and values of MBS and ABS may fall.

U.S. Government Issuers Risk. Treasury obligations may differ in their interest rates, maturities, times of issuance and other characteristics. Obligations of U.S. government agencies and authorities are supported by varying degrees of credit but generally are not backed by the full faith and credit of the U.S. government. Bonds or debentures that do not carry the backing of the full faith and credit of the U.S. government are subject to more credit risk than securities that are supported by the full faith and credit of the U.S. government. To the extent that the U.S. government has provided support to a U.S. agency or sponsored entity in the past, there can be no assurance that the U.S. government will provide support in the future if it is not obligated to do so. If a U.S. government agency or sponsored entity that is the issuer of securities in which the Fund invests is unable to meet its obligations or ceases to exist and no plan is made for repayment of securities, the performance of the Fund will be adversely affected. Similar to other issuers, changes to the financial condition or credit rating of the U.S. government or U.S. government agencies and authorities may cause the value of the Fund’s investments to decline. U.S. Treasury securities are rated AA+ by S&P Global Ratings. A downgrade of the rating of U.S. Treasury securities may cause the value of the Fund’s U.S. Treasury obligations to decline. Because U.S. government debt obligations, are often used as a benchmark for other borrowing arrangements, a downgrade could also result in higher interest rates for a range of borrowers, cause disruptions in the international bond markets and have a substantial adverse effect on the U.S. and global economy. A high national debt level may increase market pressures to meet government funding needs, which may drive debt cost higher and lead the government to issue additional debt, thereby increasing refinancing risk. A high national debt also raises concerns that the U.S. government will not be able to make principal or interest payments when they are due. If market participants determine that U.S. sovereign debt levels have become unsustainable, the value of the U.S. dollar could decline, thus increasing inflationary pressures, particularly with respect to services outsourced to non-U.S. providers and imported goods and constrain or prevent the U.S. government from implementing effective countercyclical fiscal policy in economic downturns. Direct obligations of the U.S. Treasury have historically involved little risk of loss of principal if held to maturity. However, due to fluctuations in interest rates, the market value of such securities may vary during the period that shareholders own shares of the Fund. Notwithstanding that U.S. Treasury obligations are backed by the full faith and credit of the United States, circumstances could arise that would prevent the timely payment of interest or principal, which would result in losses to the Fund.

U.S. Agency Debt Risk. The Fund invests in unsecured bonds or debentures issued or guaranteed by the U.S. government or one of its agencies or sponsored entities. Certain debt issuances by U.S. government agencies or sponsored entities, including, among others, the Federal National Mortgage Association (“Fannie Mae”), the Federal Home Loan Mortgage Corporation (“Freddie Mac”), the Federal Home Loan Banks (“FHLB”), and the Tennessee Valley Authority (“TVA”), are backed only by the general creditworthiness and reputation of the U.S. government agency or sponsored entity and not the full faith and credit of the U.S. government and, as a result, are subject to additional credit risk. To the extent that the U.S. government has provided support to a U.S. agency or sponsored entity in the past, there can be no assurance that the U.S. government will provide support in the future if it is not obligated to do so. Ginnie Mae securities and certain foreign government debt issuances guaranteed by the U.S. government are backed by the full faith and credit of the U.S. government.

U.S. Agency Mortgage-Backed Securities Risk. The Fund invests in securities backed by pools of mortgages issued or guaranteed by the U.S. government or one of its agencies or sponsored entities, including the Federal National Mortgage Association (“Fannie Mae”), the Government National Mortgage Association (“GNMA”) or the Federal Home Loan Mortgage Corporation (“Freddie Mac”) or (Fannie Mae, GNMA or Freddie Mac). While securities guaranteed by Ginnie Mae are backed by the full faith and credit of the U.S. government, securities issued by Fannie Mae and Freddie Mac are not backed by the full faith and credit of the U.S. government, and there can be no assurance that the U.S. government would provide financial support to its agencies or sponsored entities where it is not obligated to do so. Bonds or debentures that do not carry the backing of the full faith and credit of the U.S. government are subject to more credit risk than securities that are supported by the full faith and credit of the U.S. government. To the extent that the U.S. government has provided support to a U.S. agency or sponsored entity in the past, there can be no assurance that the U.S. government will provide support in the future if it is not obligated to do so. If a U.S. government agency or sponsored entity that is the issuer of securities in which the Fund invests is unable to meet its obligations or ceases to exist and no plan is made for repayment of securities, the performance of the Fund will be adversely affected.

Mortgage-backed securities (“MBS”) represent interests in “pools” of mortgages and, due to the nature of these loans they represent, are subject to prepayment and extension risk. Prepayment risk is the risk that, during periods of falling interest rates, an issuer of mortgages and other fixed-income securities may be able to repay principal prior to the security’s maturity. This may cause the Fund to have to reinvest in securities with a lower yield or higher risk of default, resulting in a decline in the Fund’s income or return potential.

MBS are also subject to extension risk, which is the risk that when interest rates rise, certain MBS will be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in income and potentially in the value of the investment.

Because of prepayment and extension risks, MBS react differently to changes in interest rates than other bonds. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain MBS. These securities are also subject to the risk of default on the underlying mortgage loans, particularly during periods of economic downturn.

The Fund seeks to obtain exposure to the fixed-rate portion of U.S. agency mortgage pass-through securities primarily through TBA securities, or TBA transactions. TBAs refer to a commonly used mechanism for the forward settlement of U.S. agency MBS, and not to a separate type of MBS. Default or bankruptcy of a counterparty to a TBA transaction would expose the Fund to possible losses because of adverse market action, expenses or delays in connection with the purchase or sale of the pools of mortgage pass-through securities specified in the TBA transaction.

Commercial Mortgage-Backed Securities Risk. The CMBS in which the Fund invests may be issued by entities, such as banks, mortgage lenders or other institutions. These entities are not backed by the full faith and credit of the U.S. government, and there can be no assurance that the U.S. government would provide financial support to its agencies or instrumentalities where it is not obligated to do so.

CMBS depend on cash flows generated by underlying commercial real-estate loans, receivables or other assets, and can be significantly affected by changes in interest rates, the availability of information concerning the underlying assets and their structure, and the creditworthiness of the originators of the underlying assets.

Due to the nature of the loans they represent, CMBS are subject to a greater degree of prepayment and extension risk than many other forms of fixed-income securities. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain CMBS. Certain CMBS are issued in several classes with different levels of yield and credit protection. The Fund’s investments in CMBS with several classes may be in the lower classes that have greater risks than the higher classes, including greater interest rate, credit, prepayment and extension risks.

In addition, the value of CMBS may be adversely affected by regulatory or tax changes. CMBS issued by non-government entities may offer higher yields than those issued by government entities, but also may be subject to greater volatility than government issues. In the recent past, the market for CMBS has experienced volatility and reduced liquidity.

Floating Rate Securities Risk. Securities with floating or variable interest rates can be less sensitive to interest rate changes than securities with fixed interest rates, but may decline in value if their interest rates do not rise as much, or as quickly, as interest rates in general. Conversely, floating rate securities will not generally increase in value if interest rates decline. A decline in interest rates may result in a reduction in income received from floating rate securities held by the Fund and may adversely affect the value of the Fund’s shares. Generally, floating rate securities carry lower yields than fixed securities of the same maturity. The interest rate for a floating rate security resets or adjusts periodically by reference to a benchmark interest rate. The impact of interest rate changes on floating rate investments is typically mitigated by the periodic interest rate reset of the investments. Securities with longer durations tend to be more sensitive to interest rate changes, usually making them more volatile than securities with shorter durations. Floating rate securities generally are subject to legal or contractual restrictions on resale, may trade infrequently, and their value may be impaired when the Fund needs to liquidate such loans. Benchmark interest rates may not accurately track market interest rates.

Although floating rate securities are less sensitive to interest rate risk than fixed-rate securities, they are subject to credit risk and default risk, which could impair their value.

Collateralized Debt Obligations Risk. In addition to the typical risks associated with fixed-income securities and asset-backed securities, CDOs, including collateralized loan obligations, carry additional risks including, but not limited to: (i) the possibility that distributions from collateral securities will not be adequate to make interest or other payments; (ii) the risk that the collateral may default or decline in value or be downgraded, if rated by a nationally recognized statistical rating organization; (iii) the Fund may invest in tranches of CDOs that are subordinate to other tranches; (iv) the structure and complexity of the transaction and the legal documents could lead to disputes among investors regarding the characterization of proceeds; (v) the investment return achieved by the Fund could be significantly different than those predicted by financial models; (vi) the lack of a readily available secondary market for CDOs; (vii) the risk of forced “fire sale” liquidation due to technical defaults such as coverage test failures; and (viii) the CDO’s manager may perform poorly.

Municipal Securities Risk. Municipal securities include both general obligation bonds (bonds secured by the full faith and credit of the issuer) and limited obligation bonds (or “Revenue Bonds”). All municipal securities are subject to the risk that litigation, legislation or other political events, local business or economic conditions, credit rating downgrades, or the bankruptcy of the issuer could have a significant effect on an issuer’s ability to make payments of principal and/or interest or otherwise affect the value of such securities. Additionally, certain municipal securities may be issued by entities with limited taxing authority, which could limit or prevent tax increases necessary to make continued payments of principal and interest.

Municipal securities can be significantly affected by political or economic changes, including changes made in the law after issuance of the securities, as well as uncertainties in the municipal market related to taxation, legislative changes or the rights of municipal security holders, including in connection with an issuer insolvency. There is also the risk that corruption may negatively affect municipal issuers, including corruption related to a particular project from which payments on a security are derived, resulting in delays and cost overruns.

There may be less publicly available information on the financial condition of municipal security issuers than for issuers of other securities. As a result, municipal securities may be more difficult for the Fund to value accurately than the securities of public companies. Municipal securities may also be harder to buy and sell compared to taxable bonds and non-municipal securities, especially on short notice. Because the Fund invests a significant portion of its portfolio in municipal securities, the Fund’s portfolio is subject to greater exposure to illiquidity risk than a fund that invests in comparable taxable bonds or non-municipal securities.

The Fund and BFA will rely on the opinion of issuers’ bond counsel on the tax-exempt status of interest on municipal bonds. Neither the Fund nor BFA will independently review the bases for those tax opinions, which may ultimately be determined to be incorrect, potentially resulting in the Fund and its shareholders being subject to substantial tax liabilities. In addition, changes in the financial condition of an individual municipal issuer can affect the overall municipal market.

Revenue Bonds are backed by current or anticipated revenues from a specific project or specific assets and can be negatively affected by the discontinuance of the tax benefits supporting the project or assets or the inability to collect revenues from the project or the assets. Additionally, the market values of Revenue Bonds may decline in times of higher inflation to the extent that revenues are fixed income streams. In other instances, the prices that an issuer is

able to charge users of its assets may be linked to inflation, whether by government regulation, contractual arrangement or other factors. Rising interest rates could result in higher costs of capital for certain issuers, which could negatively impact their ability to meet payment obligations. In this case, changes in the rate of inflation may affect the issuer’s revenues. Because many municipal securities are issued to finance projects, such as those related to education, health care, housing, transportation, utilities, and water and sewer, conditions in one or more of these sectors can affect the overall municipal market. Adverse conditions and developments affecting a particular project can result in lower revenues to an issuer of the municipal securities and, by extension, adversely affect payments of principal and interest on, or the market value of, such securities.

Additionally, certain municipal securities are issued by entities dependent on revenue from a particular sector and thus are subject to the specific risks associated with that sector.

Corporate Loans Risk. Commercial banks and other financial institutions or institutional investors make corporate loans to companies that need capital to grow or restructure. Borrowers generally pay interest on corporate loans at rates that change in response to changes in market interest rates or the prime rates of U.S. banks. As a result, the value of corporate loan investments is generally less exposed to the adverse effects of shifts in market interest rates than investments that pay a fixed rate of interest. However, because the trading market for certain corporate loans may be less developed than the secondary market for bonds and notes, the Fund may experience difficulties in selling its corporate loans. Transactions in corporate loans may settle on a delayed basis. As a result, the proceeds from the sale of corporate loans may not be readily available to make additional investments. To the extent the extended settlement process gives rise to short-term liquidity needs, the Fund may hold additional cash, sell investments or temporarily borrow from banks and other lenders. Leading financial institutions often act as agent for a broader group of lenders, generally referred to as a syndicate. The syndicate’s agent arranges the corporate loans, holds collateral and accepts payments of principal and interest. If the agent develops financial problems, the Fund may not recover its investment or recovery may be delayed. By investing in a corporate loan, the Fund may become a member of the syndicate.

The market for corporate loans may be subject to irregular trading activity and wide bid/ask spreads.

The corporate loans in which the Fund invests are subject to the risk of loss of principal and income. Although borrowers frequently provide collateral to secure repayment of these obligations they do not always do so. If they do provide collateral, the value of the collateral may not completely cover the borrower’s obligations at the time of a default. If a borrower files for protection from its creditors under the U.S. bankruptcy laws, these laws may limit the Fund’s rights to its collateral. In addition, the value of collateral may erode during a bankruptcy case. In the event of a bankruptcy, the holder of a corporate loan may not recover its principal, may experience a long delay in recovering its investment and may not receive interest during the delay.

Asset Class Risk. The securities or other assets in the Fund’s portfolio may underperform in comparison to the securities markets in general or of funds that track other indexes, industries, groups of industries, markets, market segments, asset classes or sectors including the futures market. Various types of securities, currencies and indexes or assets may experience cycles of outperformance and underperformance in comparison to the general financial markets depending upon a number of factors including, among other things, inflation, interest rates, productivity, global demand for local products or resources, and regulation and governmental controls.

Assets Under Management (AUM) Risk. From time to time, an Authorized Participant, a third-party investor, the Fund’s adviser or an affiliate of the Fund’s adviser, or a fund may invest in the Fund and hold its investment for a specific period of time in order to facilitate commencement of the Fund’s operations or to allow the Fund to achieve size or scale. There can be no assurance that any such entity would not redeem its investment or that the size of the Fund would be maintained at such levels, which could negatively impact the Fund.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund, and none of those Authorized Participants is obligated to engage in creation and/or redemption transactions. The Fund has a limited number of institutions that may act as Authorized Participants on an agency basis (i.e., on behalf of other market participants). To the extent that Authorized Participants exit the business or are unable to proceed with creation or redemption orders with respect to the Fund and no other Authorized Participant is able to step forward to create or redeem Creation Units, Fund shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting. Authorized Participant concentration risk may be heightened because ETFs, such as the Fund, that invest in securities issued by non-U.S.

issuers or other securities or instruments that are less widely traded often involve greater settlement and operational issues and capital costs for Authorized Participants, which may limit the availability of Authorized Participants.

Cybersecurity Risk. Cybersecurity failures by, or breaches of, the systems of the Fund’s adviser, distributor and other service providers (including, but not limited to, index and benchmark providers, fund accountants, custodians, transfer agents and administrators), or the issuers of securities in which the Fund invests have the ability to cause disruptions and impact business operations, potentially resulting in: financial losses; interference with the Fund’s ability to calculate its NAV; disclosure of confidential trading information; impediments to trading; submission of erroneous trades or erroneous creation or redemption orders; the inability of the Fund or its service providers to transact business; violations of applicable privacy and other laws; regulatory fines, penalties, reputational damage, reimbursement or other compensation costs; or additional compliance costs. In addition, cyberattacks may render records of Fund assets and transactions, shareholder ownership of Fund shares, and other data integral to the functioning of the Fund inaccessible, inaccurate or incomplete. Substantial costs may be incurred by the Fund in order to resolve or prevent cyber incidents in the future. While the Fund has established business continuity plans in the event of, and risk management systems to prevent, such cyber incidents, there are inherent limitations in such plans and systems, including the possibility that certain risks have not been identified, that prevention and remediation efforts will not be successful or that cyberattacks will go undetected. Furthermore, the Fund cannot control the cybersecurity plans and systems put in place by service providers to the Fund or issuers in which the Fund invests. The Fund and its shareholders could be negatively impacted as a result.

High Portfolio Turnover Risk. Participation in TBA transactions may significantly increase the Fund’s portfolio turnover rate and may cause the Fund to pay higher capital gain distributions to shareholders (which may be taxable) than other funds that do not participate in TBA transactions. The Fund may engage in active and frequent trading of its portfolio securities. High portfolio turnover (considered by the Fund to mean higher than 100% annually) may result in increased transaction costs to the Fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of the securities and on reinvestment in other securities. The sale of the Fund’s portfolio securities may result in the realization and/or distribution to shareholders of higher capital gains or losses as compared to a fund with less active trading policies, such as index ETFs. Given the frequency of sales, in any given year, all or a substantial portion of such gain or loss may be short-term capital gain or loss and, in the event of either net short-term or long-term realized gain, would increase an investor’s tax liability unless shares are held through a tax-deferred or exempt vehicle. These effects of higher than normal portfolio turnover may adversely affect Fund performance.

Illiquid Investments Risk. The Fund may not acquire any illiquid investment if, immediately after the acquisition, the Fund would have invested more than 15% of its net assets in illiquid investments. An illiquid investment is any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without significantly changing the market value of the investment. Liquid investments may become illiquid after purchase by the Fund, particularly during periods of market turmoil. There can be no assurance that a security or instrument that is deemed to be liquid when purchased will continue to be liquid for as long as it is held by the Fund, and any security or instrument held by the Fund may be deemed an illiquid investment pursuant to

the Fund’s liquidity risk management program. To the extent the Fund holds illiquid investments, the illiquid investments may reduce the returns of the Fund because the Fund may be unable to transact at advantageous times or prices. An investment may be illiquid due to, among other things, the reduced number and capacity of traditional market participants to make a market in securities or instruments or the lack of an active market for such securities or instruments. To the extent that the Fund invests in securities or instruments with substantial market and/or credit risk, the Fund will tend to have increased exposure to the risks associated with illiquid investments. Illiquid investments may be harder to value, especially in changing markets. If the Fund is forced to sell underlying investments at reduced prices or under unfavorable conditions to meet redemption requests or for other cash needs, the Fund may suffer a loss. This may be magnified in a rising interest rate environment or other circumstances where redemptions from the Fund may be greater than normal. Other market participants may be attempting to liquidate holdings at the same time as the Fund, causing increased supply of the Fund’s underlying investments in the market and contributing to illiquid investments risk and downward pricing pressure. In addition, if the Fund is limited in its ability to sell illiquid investments during periods when shareholders are redeeming their shares, the Fund will need to sell liquid securities to meet redemption requests and illiquid securities will become a larger portion of the Fund’s holdings. During periods of market volatility, liquidity in the market for the Fund’s shares may be impacted by the liquidity in the market for the underlying securities or instruments held by the Fund, which could lead to the Fund’s shares trading at a premium or discount to the Fund’s NAV.

Infectious Illness Risk. A widespread outbreak of an infectious illness, such as the COVID-19 pandemic, may adversely affect the economies of many nations and the global economy and may impact individual issuers and capital markets in ways that cannot be foreseen.

An infectious illness outbreak may result in travel restrictions, closed international borders, disruption of healthcare services, prolonged quarantines, cancellations, supply chain disruptions, lower consumer demand, temporary and permanent closures of businesses, layoffs, defaults and other significant economic, social and political impacts, as well as general concern and uncertainty.

An infectious illness outbreak may result in extreme volatility, severe losses, credit deterioration of issuers, and disruptions in markets, which could adversely impact the Fund and its investments, including impairing any hedging activity.

Certain local markets may be subject to closures. Any suspension of trading in markets in which the Fund invests will have an impact on the Fund and its investments and will impact the Fund’s ability to purchase or sell securities in such markets. Market or economic disruptions could result in elevated tracking error and increased premiums or discounts to the Fund’s NAV. Additionally, an outbreak could impair the operations of the Fund’s service providers, including BFA, which could adversely impact the Fund.

Governmental and quasi-governmental authorities and regulators throughout the world may respond to an outbreak and any resulting economic disruptions with a variety of fiscal and monetary policy changes, including direct capital infusions into companies and other issuers, new monetary policy tools, and changes in interest rates. A reversal of these policies, or the ineffectiveness of such policies, is likely to increase market volatility, which could adversely affect the Fund’s investments.

An outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally, which could adversely affect the Fund and its investments and could result in increased premiums or discounts to the Fund’s NAV.

Despite the development of vaccines, the duration of the COVID-19 pandemic and its effects cannot be predicted with certainty.

Investment Companies and ETFs Risk. Subject to the limitations set forth in the Investment Company Act and the rules thereunder, the Fund may acquire shares in other investment companies and in ETFs, some of which may be affiliated investment companies. The market value of the shares of other investment companies and ETFs may differ from their net asset value. As an investor in investment companies and ETFs, the Fund would bear its ratable share of that entity’s expenses, including its investment advisory and administration fees, while continuing to pay its own advisory and administration fees and other expenses (to the extent not offset by BFA through waivers). As a result, shareholders will be absorbing duplicate levels of fees with respect to investments in other investment companies and ETFs (to the extent not offset by BFA through waivers).

The securities of other investment companies and ETFs in which the Fund may invest may be leveraged. As a result, the Fund may be indirectly exposed to leverage through an investment in such securities. An investment in securities of other investment companies and ETFs that use leverage may expose the Fund to higher volatility in the market value of such securities and the possibility that the Fund’s long-term returns on such securities (and, indirectly, the long-term returns of shares of the Fund) will be diminished.

As with other investments, investments in other investment companies, including ETFs, are subject to market and selection risk. To the extent the Fund is held by an affiliated fund, the ability of the Fund itself to hold other investment companies may be limited.

Issuer Risk. The performance of the Fund depends on the performance of individual securities to which the Fund has exposure. The Fund may be adversely affected if an issuer of underlying securities held by the Fund is unable or unwilling to repay principal or interest when due. Any issuer of these securities may perform poorly, causing the value of its securities to decline. Poor performance may be caused by poor management decisions, competitive pressures, changes in technology, expiration of patent protection, disruptions in supply, labor problems or shortages, corporate restructurings, fraudulent disclosures, credit deterioration of the issuer or other factors. Changes to the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline.

Large Shareholder and Large-Scale Redemption Risk. Certain shareholders, including an Authorized Participant, a third-party investor, the Fund’s adviser or an affiliate of the Fund’s adviser, a market maker, or another entity, may from time to time own or manage a substantial amount of Fund shares or may invest in the Fund and hold their investment for a limited period of time. These shareholders may also pledge or loan Fund shares (to secure financing or otherwise), which may result in the shares becoming concentrated in another party. There can be no assurance that any large shareholder or large group of shareholders would not redeem their investment or that the size of the Fund would be maintained. Redemptions of a large number of Fund shares by these shareholders may adversely affect the Fund’s liquidity and net assets. To the extent the Fund permits redemptions in cash, these redemptions may force the Fund to sell portfolio securities when it might not otherwise do so, which may negatively impact the Fund’s NAV, have a material effect on the market price of the Shares and increase the Fund’s brokerage costs and/or accelerate the realization of taxable income and/or gains and cause the Fund to make taxable distributions to its shareholders earlier than the Fund otherwise would have. In addition, under certain circumstances, non-redeeming shareholders may be treated as receiving a disproportionately large taxable distribution during or with respect to such tax year. The Fund also may be required to sell its more liquid Fund investments to meet a large redemption, in which case the Fund’s remaining assets may be less liquid, more volatile, and more difficult to price. To the extent these large shareholders transact in shares on the secondary market, such transactions may account for a large percentage of the trading volume for the shares of the Fund and may, therefore, have a material upward or downward effect on the market price of the Fund shares. In addition, large purchases of Fund shares may adversely affect the Fund’s performance to the extent that the Fund is delayed in investing new cash and is required to maintain a larger cash position than it ordinarily would, diluting its investment returns.

Market Risk. The Fund could lose money over short periods due to short-term market movements and over longer periods during more prolonged market downturns. The value of a financial instrument or other asset may decline due to changes in general market conditions, economic trends or events that are not specifically related to the particular instrument or asset, or factors that affect one or more issuers, counterparties, exchanges, countries, regions, markets, industries, sectors or asset classes, as applicable. Local, regional or global events such as war, acts of terrorism, public health issues, recessions, the prospect or occurrence of a sovereign default or other financial crisis, or other events could have a significant impact on the Fund and its investments and could result in increased premiums or discounts to the Fund’s NAV. Changes in market and economic conditions generally do not have the same impact on all types of instruments and assets.

per share. Given the high level of transparency of the Fund’s holdings, BFA believes that the trading experience of the Fund should be similar to that of index-based ETFs. However, ETFs that do not seek to replicate the performance of a specified index have a limited trading history and, therefore, there can be no assurance as to whether, and/or the extent to which, the Fund’s shares will trade at premiums or discounts to NAV. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND’S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.

Non-Diversification Risk. To the extent the Fund is non-diversified, the Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund’s performance may be adversely affected, the Fund’s shares may experience greater price volatility and the Fund may be more susceptible to the risks associated with these particular issuers or to a single economic, political or regulatory occurrence affecting these issuers.

Non-U.S. Issuers Risk. The Fund may invest in U.S. dollar-denominated securities of non-U.S. corporate issuers. Securities issued by non-U.S. issuers have different risks from securities issued by U.S. issuers. These risks include differences in accounting, auditing and financial reporting standards, the possibility of expropriation or confiscatory taxation, adverse changes in investment or exchange control regulations, political instability which could affect U.S. investments in non-U.S. countries, uncertainties of transnational litigation, and potential restrictions on the flow of international capital, including the possible seizure or nationalization of the securities issued by non-U.S. issuers held by the Fund. Non-U.S. issuers may be subject to less governmental regulation than U.S. issuers. Moreover, individual non-U.S. economies may differ favorably or unfavorably from the U.S. economy in such respects as growth of gross domestic product, rate of inflation, capital reinvestment, resource self-sufficiency and balance of payment positions. Unfavorable political, economic or governmental developments in non-U.S. countries could affect the payment of a security’s principal and interest. Securities issued by non-U.S. issuers may also be less liquid than, and more difficult to value than, securities of U.S. issuers. In addition, the value of these securities may fluctuate due to changes in the exchange rate of the issuer’s local currency against the U.S. dollar.

Risk of Investing in Emerging Markets. Investments in emerging market issuers may be subject to a greater risk of loss than investments in issuers located or operating in more developed markets. This is due to, among other things, the potential for greater market volatility, currency devaluations, lower trading volume, higher levels of inflation, social, political or economic instability, greater risk of a market shutdown and more governmental limitations on foreign investments in emerging market countries than are typically found in more developed markets. Certain emerging markets countries have experienced economic recessions causing a negative effect on the economies and securities markets of such emerging countries.

Some countries in which the Fund may invest may experience economic instability, including instability resulting from substantial rates of inflation or significant devaluations of their currency, or economic recessions, which would have a negative effect on the economies and securities markets of their economies. Some of these countries may also impose restrictions on the exchange or export of currency or adverse currency exchange rates and may be characterized by a lack of available currency hedging instruments.

Disparities of wealth, the pace and success of democratization and ethnic, religious and racial disaffection, among other factors, may exacerbate social unrest, violence and labor unrest in some of the countries in which the Fund may invest. Unanticipated or sudden political or social developments may result in sudden and significant investment losses.

Companies in many emerging markets are not subject to the same degree of regulatory requirements, accounting standards or auditor oversight as companies in more developed countries, and as a result, information about the securities in which the Fund invests may be less reliable or complete. Moreover, emerging markets often have less reliable securities valuations and greater risks associated with custody of securities than developed markets. There may be significant obstacles to obtaining information necessary for investigations into or litigation against companies and shareholders may have limited legal remedies. In addition, emerging markets often have greater risk of capital controls through such measures as taxes or interest rate control than developed markets. Certain emerging market countries may also lack the infrastructure necessary to attract large amounts of foreign trade and investment. Chronic structural public sector deficits in some countries in which the Fund may invest may adversely impact securities held by the Fund.

Local securities markets in emerging market countries may trade a small number of securities and may be unable to respond effectively to changes in trading volume, potentially making prompt liquidation of holdings difficult or impossible at times. Settlement procedures in emerging market countries are frequently less developed and reliable than those in the U.S. (and other developed countries). In addition, significant delays may occur in certain markets in registering the transfer of securities.

Risk of Investing in the U.S. A decrease in imports or exports, changes in trade regulations, inflation and/or an economic recession in the U.S. may have a material adverse effect on the U.S. economy and the securities listed on U.S. exchanges. Proposed and adopted policy and legislative changes in the U.S. are changing many aspects of financial, commercial, public health, environmental, and other regulation and may have a significant effect on U.S. markets generally, as well as on the value of certain securities. Governmental agencies project that the U.S. will continue to maintain elevated public debt levels for the foreseeable future. Although elevated debt levels do not necessarily indicate or cause economic problems, elevated public debt service costs may constrain future economic growth. Circumstances could arise that could prevent the timely payment of interest or principal on U.S. government debt, such as reaching the legislative “debt ceiling.” Such non-payment would result in substantial negative consequences for the U.S. economy and the global financial system.

If U.S. relations with certain countries deteriorate, it could adversely affect U.S. issuers as well as non-U.S. issuers that rely on the U.S. for trade. The U.S. has also experienced increased internal unrest and discord. If these trends were to continue, it may have an adverse impact on the U.S. economy and the issuers in which the Fund invests.

Sovereign and Quasi-Sovereign Obligations Risk. An investment in sovereign or quasi-sovereign debt obligations involves special risks not present in corporate debt obligations. Sovereign debt includes securities issued by or guaranteed by a non-U.S. sovereign government, and quasi-sovereign debt includes securities issued by or guaranteed by an entity affiliated with or backed by a sovereign government. The issuer of the sovereign debt that controls the repayment of the debt may be unable or unwilling to repay principal or interest when due, and the Fund may have limited recourse in the event of a default. Sovereign obligations may differ from other securities in their interest rates, maturities, times of issuance and other characteristics and may provide relatively lower returns than those of other securities. Similar to other issuers, changes to the financial condition or credit rating of a government may cause the value of a sovereign debt obligation to decline. During periods of economic uncertainty, the market prices of sovereign debt may be more volatile than prices of U.S. debt obligations and may affect the or Fund’s NAV. Quasi-sovereign debt obligations are typically less liquid and less standardized than sovereign debt obligations. These risks may be more pronounced with respect to non-U.S. sovereign debt than with respect to U.S. government debt.

The Fund may also be subject to certain other risks associated with its investments and investment strategies.

Borrowing Risk. Borrowing may exaggerate changes in the NAV of Fund shares and in the return on the Fund’s portfolio. Borrowing will cost the Fund interest expense and other fees. The costs of borrowing may reduce the Fund’s return. Borrowing may also cause the Fund to liquidate positions when it may not be advantageous to do so to satisfy its obligations.

Expense Risk. Fund expenses are subject to a variety of factors, including fluctuations in the Fund’s net assets. Accordingly, actual expenses may be greater or less than those indicated. For example, to the extent that the Fund’s net assets decrease due to market declines or redemptions, the Fund’s expenses will increase as a percentage of Fund net assets. During periods of high market volatility, these increases in the Fund’s expense ratio could be significant.

Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human errors, processing and communication errors, errors of the Fund’s service providers, counterparties or other third parties, failed or inadequate internal or external processes, and technology or systems failures. The use of certain investment strategies that involve manual or additional processing, such as over-the-counter derivatives, increases these risks. While service providers are required to have appropriate operational risk management policies and procedures, their methods of operational risk management may differ from those of the Fund in the setting of priorities, the personnel and resources available or the effectiveness of relevant controls. The Fund and BFA seek to reduce these operational risks through controls, procedures and oversight. However, it is not possible to identify all of the operational risks that may affect the Fund or to develop processes and controls that completely eliminate or mitigate the occurrence or effects of such failures. The Fund, including its performance and continued operation, and its shareholders could be negatively impacted as a result.

Reliance on Advisor Risk. The Fund is dependent upon services and resources provided by BFA, and therefore BFA’s parent, BlackRock, Inc. BFA is not required to devote its full time to the business of the Fund and there is no guarantee or requirement that any investment professional or other employee of BFA will allocate a substantial portion of his or her time to the Fund. The loss of, or changes in, BFA’s personnel could have a negative effect on the performance or the continued operation of the Fund.

Securities Lending Risk. The Fund may engage in securities lending. Securities lending involves the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund could also lose money in the event of a decline in the value of collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund. BlackRock Institutional Trust Company, N.A. (“BTC”), the Fund’s securities lending agent, will take into account the tax impact to shareholders of substitute payments for dividends when managing the Fund’s securities lending program. Substitute payments received by the Fund with respect to municipal securities lent, if any, will not constitute tax-exempt interest income to the Fund.

Short Sales Risk. Because making short sales in securities that it does not own exposes the Fund to the risks associated with those securities, such short sales involve speculative exposure risk. The Fund will incur a loss as a result of a short sale if the price of the security increases between the date of the short sale and the date on which the Fund replaces the security sold short. The Fund will realize a gain if the security declines in price between those dates. As a result, if the Fund makes short sales in securities that increase in value, it will likely underperform similar funds that do not make short sales in securities they do not own. There can be no assurance that the Fund will be able to close out a short sale position at any particular time or at an acceptable price. Although the Fund’s gain is limited to the amount at which it sold a security short, its potential loss is limited only by the maximum attainable price of the security, less the price at which the security was sold. The Fund may also pay transaction costs and borrowing fees in connection with short sales.

A description of the Trust’s policies and procedures with respect to the disclosure of the Fund’s portfolio securities is available in the Fund’s Statement of Additional Information (“SAI”). The Fund discloses its portfolio holdings daily at www.blackrock.com. Fund fact sheets provide information regarding the Fund’s top holdings and may be requested by calling 1-800-474-2737.

Investment Adviser and Sub-Advisers. The Fund’s investment adviser is BlackRock Fund Advisors. The Fund’s sub-advisers are BlackRock International Limited (“BIL”) and BlackRock (Singapore) Limited (“BSL” and together with BIL, the “Sub-Advisers”). Where applicable, the use of the term BFA also refers to the Fund’s sub-advisers. As investment adviser, BFA has overall responsibility for the general management and administration of the Fund. BFA provides an investment program for the Fund and manages the investment of the Fund’s assets. In managing the Fund, BFA may draw upon the research and expertise of its asset management affiliates with respect to certain portfolio securities. In seeking to achieve the Fund’s investment objectives, BFA uses teams of portfolio managers, investment strategists and other investment specialists. This team approach brings together many disciplines and leverages BFA’s extensive resources.

Pursuant to the Investment Advisory Agreement between BFA and the Trust (entered into on behalf of the Fund), BFA is responsible for substantially all expenses of the Fund, except the management fees, interest expenses, taxes, expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, distribution fees or expenses, litigation expenses and any extraordinary expenses (as determined by a majority of the Trustees who are not “interested persons” of the Trust).

For its investment advisory services to the Fund, BFA is paid a management fee from the Fund, based on a percentage of the Fund’s average daily net assets, at an annual rate of 0.50%.

BFA has contractually agreed to waive a portion of its management fees in an amount equal to the aggregate Acquired Fund Fees and Expenses, if any, attributable to investments by the Fund in other equity and fixed-income mutual funds and ETFs advised by BFA or its affiliates through June 30, 2025. BFA has also contractually agreed to waive a portion of its management fees by an amount equal to the aggregate Acquired Fund Fees and Expenses, if any, attributable to investments by the Fund in money market funds advised by BFA or its affiliates through June 30, 2025. The agreement (with respect to either waiver) may be terminated upon 90 days’ notice by a majority of the non-interested trustees of the Trust or by a vote of a majority of the outstanding voting securities of the Fund. BFA has contractually agreed to waive 0.10% of its management fee payable by the Fund through June 30, 2025. BFA may also from time to time voluntarily waive and/or reimburse fees or expenses in order to limit total annual fund operating expenses (excluding acquired fund fees and expenses, if any). Any such voluntary waiver or reimbursement may be eliminated by BFA at any time.

For the fiscal year ended July 31, 2023, BFA received management fees, net of any applicable waivers and/or reimbursement, at the annual rate of 0.37% of the Fund’s average daily net assets.

BFA has entered into separate sub-advisory agreements (each, a “Sub-Advisory Agreement”) with BIL and BSL, each an affiliate of BFA. Under each Sub-Advisory Agreement, BFA pays the respective Sub-Adviser for services it provides for that portion of the Fund for which the Sub-Adviser acts as sub-adviser a fee equal to a percentage of the management fee paid to BFA under the Investment Advisory Agreement between BFA and the Trust.

BFA is located at 400 Howard Street, San Francisco, CA 94105. It is an indirect wholly-owned subsidiary of BlackRock, Inc. (“BlackRock”). As of September 30, 2023, BFA and its affiliates provided investment advisory services for assets of approximately $9.101 trillion. BIL is a registered investment adviser, organized in 1999, located in the U.K. at Exchange Place One, 1 Semple Street, Edinburgh, EH3 8BL, United Kingdom. BSL is a registered investment adviser, organized in 2000, located in Singapore at 20 Anson Road #18-01, 079912, Singapore.

A discussion of the basis for the approval by the Board of the Investment Advisory Agreement with BFA, the Sub-Advisory Agreement between BFA and BIL and the Sub-Advisory Agreement between BFA and BSL is included in the Fund’s annual report for the period ending July 31, 2023.

From time to time, a manager, analyst, or other employee of BlackRock or its affiliates may express views regarding a particular asset class, company, security, industry, or market sector. The views expressed by any such person are the views of only that individual as of the time expressed and do not necessarily represent the views of BlackRock or any other person within the BlackRock organization. Any such views are subject to change at any time based upon market or other conditions and BlackRock disclaims any responsibility to update such views. These views may not be relied on as investment advice and, because investment decisions for the Fund are based on numerous factors, may not be relied on as an indication of trading intent on behalf of the Fund.

Portfolio Managers. Rick Rieder, Samir Lakhani, Jacob Caplain, Dylan Price, and Charlotte Widjaja (the “Portfolio Managers”) are jointly and primarily responsible for the day-to-day management of the Fund. Mr. Rieder has been employed by BFA or its affiliates as a portfolio manager since 2009. Mr. Lakhani has been employed by BFA or its affiliates as a portfolio manager since 2009. Mr. Caplain has been employed by BFA or its affiliates as a portfolio manager since 2012. Mr. Price has been employed by BFA or its affiliates as a portfolio manager since 2015. Ms. Widjaja has been employed by BFA or its affiliates as a portfolio manager since 2017. Messrs. Rieder, Lakhani, Caplain, Price and Ms. Widjaja have been Portfolio Managers of the Fund since 2023.

The Fund’s SAI provides additional information about the Portfolio Managers’ compensation, other accounts managed by the Portfolio Managers and the Portfolio Managers’ ownership (if any) of shares in the Fund.

Administrator, Custodian and Transfer Agent. State Street Bank and Trust Company (“State Street”) is the administrator, custodian and transfer agent for the Fund.

Conflicts of Interest. The investment activities of BFA and its affiliates (including BlackRock and its subsidiaries (collectively, the “Affiliates”)), and their respective directors, officers or employees, in the management of, or their interest in, their own accounts and other accounts they manage, may present conflicts of interest that could disadvantage the Fund and its shareholders. BFA and its Affiliates provide investment management services to other funds and discretionary managed accounts that may follow investment programs similar to that of the Fund. BFA and its Affiliates are involved worldwide with a broad spectrum of financial services and asset management activities and may engage in the ordinary course of business in activities in which their interests or the interests of their clients may conflict with those of the Fund. BFA or one or more Affiliates act, or may act, as an investor, research provider, investment manager, commodity pool operator, commodity trading advisor, financier, underwriter, adviser, trader, lender, index provider, agent and/or principal, and have other direct and indirect interests in securities, currencies, commodities, derivatives and other instruments in which the Fund may directly or indirectly invest. The Fund may invest in securities of, or engage in other transactions with, companies with which an Affiliate has significant debt or equity investments or other interests. The Fund may also invest in issuances (such as structured notes) by entities for which an Affiliate provides and is compensated for cash management services relating to the proceeds from the sale of such issuances. The Fund also may invest in securities of, or engage in other transactions with, companies for which an Affiliate provides or may in the future provide research coverage. An Affiliate may have business relationships with, and purchase or distribute or sell services or products from or to, distributors, consultants or others who recommend the Fund or who engage in transactions with or for the Fund, and may receive compensation for

such services. BFA or one or more Affiliates may engage in proprietary trading and advise accounts and funds that have investment objectives similar to those of the Fund and/or that engage in and compete for transactions in the same types of securities, currencies and other instruments as the Fund. This may include transactions in securities issued by other open-end and closed-end investment companies (which may include investment companies that are affiliated with the Fund and BFA, to the extent permitted under the 1940 Act. The trading activities of BFA and these Affiliates are carried out without reference to positions held directly or indirectly by the Fund and may result in BFA or an Affiliate having positions in certain securities that are senior or junior to, or have interests different from or adverse to, the securities that are owned by the Fund.

Neither BFA nor any Affiliate is under any obligation to share any investment opportunity, idea or strategy with the Fund. As a result, an Affiliate may compete with the Fund for appropriate investment opportunities. The results of the Fund’s investment activities, therefore, may differ from those of an Affiliate and of other accounts managed by BFA or an Affiliate, and it is possible that the Fund could sustain losses during periods in which one or more Affiliates and other accounts achieve profits on their trading for proprietary or other accounts. The opposite result is also possible.

In addition, the Fund may, from time to time, enter into transactions in which BFA or an Affiliate or their directors, officers, employees or clients have an adverse interest. Furthermore, transactions undertaken by clients advised or managed by BFA or its Affiliates may adversely impact the Fund. Transactions by one or more clients or by BFA or its Affiliates or their directors, officers or employees, may have the effect of diluting or otherwise disadvantaging the values, prices or investment strategies of the Fund.

The Fund’s’ activities may be limited because of regulatory restrictions applicable to BFA or one or more Affiliates and/or their internal policies designed to comply with such restrictions.

Under a securities lending program approved by the Board, the Trust, on behalf of the Fund, has retained BlackRock Institutional Trust Company, N.A., an Affiliate of BFA, to serve as the securities lending agent for the Fund to the extent that the Fund participates in the securities lending program. For these services, the securities lending agent will receive a fee from the Fund, including a fee based on the returns earned on the Fund’s investment of the cash received as collateral for the loaned securities. In addition, one or more Affiliates may be among the entities to which the Fund may lend its portfolio securities under the securities lending program.

It is also possible that, from time to time, BFA and/or its advisory clients (including other funds and separately managed accounts) may, subject to compliance with applicable law, purchase and hold shares of the Fund. The price, availability, liquidity, and (in some cases) expense ratio of the Fund may be impacted by purchases and sales of the Fund by BFA and/or its advisory clients.

The activities of BFA and its Affiliates and their respective directors, officers or employees, may give rise to other conflicts of interest that could disadvantage the Fund and its shareholders. BFA has adopted policies and procedures designed to address these potential conflicts of interest. See the SAI for further information.

Additional shareholder information, including how to buy and sell shares of the Fund, is available free of charge by calling toll-free: 1-800-474-2737 or visiting our website at www.blackrock.com.

Buying and Selling Shares. Shares of the Fund may be acquired or redeemed directly from the Fund only in Creation Units or multiples thereof, as discussed in the Creations and Redemptions section of this Prospectus. Only an Authorized Participant (as defined in the Creations and Redemptions section below) may engage in creation or redemption transactions directly with the Fund. Once created, shares of the Fund generally trade in the secondary market in amounts less than a Creation Unit.

Shares of the Fund are listed on a national securities exchange for trading during the trading day. Shares can be bought and sold throughout the trading day like shares of other publicly-traded companies. The Trust does not impose any minimum investment for shares of the Fund purchased on an exchange or otherwise in the secondary market. The Fund’s shares trade under the ticker symbol “BINC.”

Buying or selling Fund shares on an exchange or other secondary market involves two types of costs that may apply to all securities transactions. When buying or selling shares of the Fund through a broker, you may incur a brokerage

commission and other charges. The commission is frequently a fixed amount and may be a significant proportional cost for investors seeking to buy or sell small amounts of shares. In addition, you may incur the cost of the “spread,” that is, any difference between the bid price and the ask price. The spread varies over time for shares of the Fund based on the Fund’s trading volume and market liquidity, and is generally lower if the Fund has high trading volume and market liquidity, and higher if the Fund has little trading volume and market liquidity (which is often the case for funds that are newly launched or small in size). The Fund’s spread may also be impacted by the liquidity or illiquidity of the underlying securities held by the Fund, particularly for newly launched or smaller funds or in instances of significant volatility of the underlying securities.

The Fund does not impose restrictions on the frequency of purchases and redemptions of Fund shares directly with the Fund. The Board determined not to adopt policies and procedures designed to prevent or monitor for frequent purchases and redemptions of Fund shares because the Fund generally sells and redeems its shares directly through transactions that are in-kind and/or cash, with a deadline for placing cash-related transactions no later than the close of the primary markets for the Fund’s portfolio securities. However, the Fund has taken certain measures (e.g., imposing transaction fees on purchases and redemptions of Creation Units and reserving the right to reject purchases of Creation Units under certain circumstances) to minimize the potential consequences of frequent cash purchases and redemptions by Authorized Participants, such as disruption of portfolio management, dilution to the Fund, and/or increased transaction costs. Further, the vast majority of trading in Fund shares occurs on the secondary market, which does not involve the Fund directly, and such trading is unlikely to cause many of the harmful effects of frequent cash purchases or redemptions of Fund shares.

The national securities exchange on which the Fund’s shares are listed is open for trading Monday through Friday and is closed on weekends and the following holidays (or the days on which they are observed): New Year’s Day, Martin Luther King, Jr. Day, Presidents’ Day, Good Friday, Memorial Day, Juneteenth, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. The Fund’s listing exchange is NYSE Arca.

Section 12(d)(1) of the 1940 Act generally restricts investments by investment companies, including foreign and unregistered investment companies, in the securities of other investment companies. For example, a registered investment company (the “Acquired Fund”), such as the Fund, may not knowingly sell or otherwise dispose of any security issued by the Acquired Fund to any investment company (the “Acquiring Fund”) or any company or companies controlled by the Acquiring Fund if, immediately after such sale or disposition: (i) more than 3% of the total outstanding voting stock of the Acquired Fund is owned by the Acquiring Fund and any company or companies controlled by the Acquiring Fund, or (ii) more than 10% of the total outstanding voting stock of the Acquired Fund is owned by the Acquiring Fund and other investment companies and companies controlled by them. Although SEC rules may permit registered investment companies and unit investment trusts (“Investing Funds”) that enter into an investment agreement with the Trust to invest in the Fund beyond the limits set forth in Section 12(d)(1) of the 1940 Act subject to certain terms and conditions, the Fund does not permit such investments. Accordingly, Investing Funds must adhere to the limits set forth in Section 12(d)(1) of the 1940 Act when investing in the Fund. Foreign investment companies are permitted to invest in the Fund only up to the limits set forth in Section 12(d)(1), subject to any applicable SEC no-action relief.

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 record owner of, and holds legal title to, all outstanding shares of the Fund.

Investors owning shares of the Fund are beneficial owners as shown on the records of DTC or its participants. DTC serves as the securities depository for shares of the Fund. DTC participants include securities brokers and dealers, banks, trust companies, clearing corporations and other institutions that directly or indirectly maintain a custodial relationship with DTC. As a beneficial owner of shares, you are not entitled to receive physical delivery of stock certificates or to have shares registered in your name, and you are not considered a registered owner of shares. Therefore, to exercise any right as an owner of shares, you must rely upon the procedures of DTC and its participants. These procedures are the same as those that apply to any other securities that you hold in book-entry or “street name” form.

Share Prices. The trading prices of the Fund’s shares in the secondary market generally differ from the Fund’s daily NAV and are affected by market forces such as the supply of and demand for ETF shares and shares of underlying securities held by the Fund, economic conditions and other factors.

Determination of Net Asset Value. The NAV of the Fund normally is determined once daily Monday through Friday, generally as of the close of regular trading hours of the New York Stock Exchange (“NYSE”) (normally 4:00 p.m., Eastern time) on each day that the NYSE is open for trading, based on prices at the time of closing, provided that (i) any Fund assets or liabilities denominated in currencies other than the U.S. dollar are translated into U.S. dollars at the prevailing market rates on the date of valuation as quoted by one or more data service providers and (ii) U.S. fixed-income assets may be valued as of the announced closing time for trading in fixed-income instruments in a particular market or exchange. The NAV of the Fund is calculated by dividing the value of the net assets of the Fund (i.e., the value of its total assets less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

The value of the securities and other assets and liabilities held by the Fund is determined pursuant to BFA’s valuation policies and procedures. BFA has been designated by the Board as the valuation designee for the Fund pursuant to Rule 2a-5 under the Investment Company Act.

The Fund values fixed-income portfolio securities using last available bid prices or current market quotations provided by dealers or prices (including evaluated prices) supplied by the Fund’s approved independent third-party pricing services, each in accordance with BFA’s valuation policies and procedures. Pricing services may use matrix pricing or valuation models that utilize certain inputs and assumptions to derive values. Pricing services generally value fixed-income securities assuming orderly transactions of an institutional round lot size, but the Fund may hold or transact in such securities in smaller odd lot sizes. Odd lots often trade at lower prices than institutional round lots. An amortized cost method of valuation may be used with respect to debt obligations with sixty days or less remaining to maturity unless BFA determines in good faith that such method does not represent fair value.

Generally, trading in non-U.S. securities, U.S. government securities, money market instruments and certain fixed-income securities is substantially completed each day at various times prior to the close of regular trading hours on the NYSE. The values of such securities used in computing the NAV of the Fund are determined as of such times.

When market quotations are not readily available or are believed by BFA to be unreliable, BFA will fair value the Fund’s investments in accordance with its policies and procedures. BFA may conclude that a market quotation is not readily available or is unreliable if a security or other asset or liability does not have a price source due to its lack of trading or other reasons, if a market quotation differs significantly from recent price quotations or otherwise no longer appears to reflect fair value, where the security or other asset or liability is thinly traded, when there is a significant event subsequent to the most recent market quotation, or if the trading market on which a security is listed is suspended or closed and no appropriate alternative trading market is available. A “significant event” is deemed to occur if BFA determines, in its reasonable business judgment prior to or at the time of pricing the Fund’s assets or liabilities, that the event is likely to cause a material change to the last exchange closing price or closing market price of one or more assets held by, or liabilities of, the Fund.

Fair value represents a good faith approximation of the value of an asset or liability. The fair value of an asset or liability held by the Fund is the amount the Fund might reasonably expect to receive from the current sale of that asset or the cost to extinguish that liability in an arm’s-length transaction. Valuing the Fund’s investments using fair value pricing will result in prices that may differ from current market valuations and that may not be the prices at which those investments could have been sold during the period in which the particular fair values were used.

General Policies. Dividends from net investment income, if any, generally are declared and paid monthly by the Fund. Distributions of net realized securities gains, if any, generally are declared and paid once a year, but the Trust may make distributions on a more frequent basis for the Fund. The Trust reserves the right to declare special distributions if, in its reasonable discretion, such action is necessary or advisable to preserve its status as a regulated investment company or to avoid imposition of income or excise taxes on undistributed income or realized gains.

Dividends and other distributions on shares of the Fund are distributed on a pro rata basis to beneficial owners of such shares. Dividend payments are made through DTC participants and indirect participants to beneficial owners then of record with proceeds received from the Fund.

Dividend Reinvestment Service. No dividend reinvestment service is provided by the Trust. Broker-dealers may make available the DTC book-entry Dividend Reinvestment Service for use by beneficial owners of the Fund for

reinvestment of their dividend distributions. Beneficial owners should contact their broker to determine the availability and costs of the service and the details of participation therein. Brokers may require beneficial owners to adhere to specific procedures and timetables. If this service is available and used, dividend distributions of both income and realized gains will be automatically reinvested in additional whole shares of the Fund purchased in the secondary market.

Taxes. As with any investment, you should consider how your investment in shares of the Fund will be taxed. The tax information in this Prospectus is provided as general information, based on current law. There is no guarantee that shares of the Fund will receive certain regulatory or accounting treatment. You should consult your own tax professional about the tax consequences of an investment in shares of the Fund.

Unless your investment in Fund shares is made through a tax-exempt entity or tax-deferred retirement account, such as an IRA, in which case your distributions generally will be taxable when withdrawn, you need to be aware of the possible tax consequences when the Fund makes distributions or you sell Fund shares.

Taxes on Distributions. Distributions from the Fund’s net investment income, including distributions of income from securities lending and distributions out of the Fund’s net short-term capital gains, if any, are taxable to you as ordinary income. The Fund’s distributions of net long-term capital gains, if any, in excess of net short-term capital losses are taxable as long-term capital gains, regardless of how long you have held the shares. Long-term capital gains are eligible for taxation at a maximum rate of 15% or 20% for non-corporate shareholders, depending on whether their income exceeds certain threshold amounts. Distributions from the Fund are subject to a 3.8% U.S. federal Medicare contribution tax on “net investment income,” for individuals with incomes exceeding $200,000 ($250,000 if married and filing jointly) and of estates and trusts. In general, your distributions are subject to U.S. federal income tax for the year when they are paid. Certain distributions paid in January, however, may be treated as paid on December 31 of the prior year.

Fund distributions, to the extent attributable to dividends from U.S. corporations, will be eligible for the dividends received deduction for Fund shareholders that are corporations, subject to certain hedging and holding requirements.

You may lose the ability to use foreign tax credits passed through by the Fund if your Fund shares are loaned out pursuant to a securities lending agreement.

If the Fund’s distributions exceed current and accumulated earnings and profits, all or a portion of the distributions made in the taxable year may be recharacterized as a return of capital to shareholders. Distributions in excess of the Fund’s minimum distribution requirements, but not in excess of the Fund’s earnings and profits, will be taxable to shareholders and will not constitute nontaxable returns of capital. A return of capital distribution generally will not be taxable but will reduce the shareholder’s cost basis and will result in a higher capital gain or lower capital loss when those shares on which the distribution was received are sold. Once a shareholder’s cost basis is reduced to zero, further distributions will be treated as capital gain, if the shareholder holds shares of the Fund as capital assets.

Dividends, interest and capital gains earned by the Fund with respect to securities issued by non-U.S. issuers may give rise to withholding, capital gains and other taxes imposed by non-U.S. countries. Tax conventions between certain countries and the U.S. may reduce or eliminate such taxes. If more than 50% of the total assets of the Fund at the close of a year consists of non-U.S. stocks or securities (generally, for this purpose, depositary receipts, no matter where traded, of non-U.S. companies are treated as “non-U.S.”), generally the Fund may “pass through” to you certain non-U.S. income taxes (including withholding taxes) paid by the Fund. This means that you would be considered to have received as an additional dividend your share of such non-U.S. taxes, but you may be entitled to either a corresponding tax deduction in calculating your taxable income, or, subject to certain limitations, a credit in calculating your U.S. federal income tax.

For purposes of foreign tax credits for U.S. shareholders of the Fund, foreign capital gains taxes may not produce associated foreign source income, limiting the availability of such credits for U.S. persons.

If you are neither a resident nor a citizen of the U.S. or if you are a non-U.S. entity (other than a pass-through entity to the extent owned by U.S. persons), the Fund’s ordinary income dividends (which include distributions of net short-term capital gains) will generally be subject to a 30% U.S. withholding tax, unless a lower treaty rate applies, provided that withholding tax will generally not apply to any gain or income realized by a non-U.S. shareholder in respect of any distributions of net tax-exempt income or long-term capital gains or upon the sale or other disposition of shares of the Fund.

Separately, a 30% withholding tax is currently imposed on U.S.-source dividends, interest and other income items paid to (i) foreign financial institutions, including non-U.S. investment funds, unless they agree to collect and disclose to the IRS information regarding their direct and indirect U.S. account holders and (ii) certain other foreign entities, unless they certify certain information regarding their direct and indirect U.S. owners. To avoid withholding, foreign financial institutions will need to (i) enter into agreements with the IRS that state that they will provide the IRS information, including the names, addresses and taxpayer identification numbers of direct and indirect U.S. account holders, comply with due diligence procedures with respect to the identification of U.S. accounts, report to the IRS certain information with respect to U.S. accounts maintained, agree to withhold tax on certain payments made to non-compliant foreign financial institutions or to account holders who fail to provide the required information, and determine certain other information concerning their account holders, or (ii) in the event that an applicable intergovernmental agreement and implementing legislation are adopted, provide local revenue authorities with similar account holder information. Other foreign entities may need to report the name, address, and taxpayer identification number of each substantial U.S. owner or provide certifications of no substantial U.S. ownership unless certain exceptions apply.

If you are a resident or a citizen of the U.S., by law, backup withholding at a 24% rate will apply to your distributions and proceeds if you have not provided a taxpayer identification number or social security number and made other required certifications.

Taxes When Shares are Sold. Currently, any capital gain or loss realized upon a sale of Fund shares is generally treated as a long-term gain or loss if the shares have been held for more than one year. Any capital gain or loss realized upon a sale of Fund shares held for one year or less is generally treated as short-term gain or loss, except that any capital loss on the sale of shares held for six months or less is treated as long-term capital loss to the extent that capital gain dividends were paid with respect to such shares. Any such capital gains, including from sales of Fund shares or from capital gain dividends, are included in “net investment income” for purposes of the 3.8% U.S. federal Medicare contribution tax mentioned above.

The foregoing discussion summarizes some of the consequences under current U.S. federal tax law of an investment in the Fund. It is not a substitute for personal tax advice. You may also be subject to state and local taxation on Fund distributions and sales of shares. Consult your personal tax advisor about the potential tax consequences of an investment in shares of the Fund under all applicable tax laws.

Creations and Redemptions. Prior to trading in the secondary market, shares of the Fund are “created” at NAV by market makers, large investors and institutions only in block-size Creation Units or multiples thereof. Each “creator” or authorized participant (an “Authorized Participant”) has entered into an agreement with the Distributor. An Authorized Participant is a member or participant of a clearing agency registered with the SEC, which has a written agreement with the Fund or one of its service providers that allows such member or participant to place orders for the purchase and redemption of Creation Units.

A creation transaction, which is subject to acceptance by the Distributor and the Fund, generally takes place when an Authorized Participant deposits into the Fund a designated portfolio of securities, assets or other positions (a “creation basket”), and an amount of cash (including any cash representing the value of substituted securities, assets or other positions), if any, which together approximate the holdings of the Fund in exchange for a specified number of Creation Units. Similarly, shares can be redeemed only in Creation Units, generally for a designated portfolio of securities, assets or other positions (a “redemption basket”) held by the Fund and an amount of cash (including any portion of such securities for which cash may be substituted). The Fund generally offers Creation Units partially for cash, but may, in certain circumstances, offer Creation Units solely for cash or solely in-kind. Except when aggregated in Creation Units, shares are not redeemable by the Fund. Creation and redemption baskets may differ and the Fund will accept “custom baskets.” More information regarding custom baskets is contained in the Fund’s 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 an acceptable form under the authorized participant agreement.

Only an Authorized Participant may create or redeem Creation Units with the Fund. Authorized Participants may create or redeem Creation Units for their own accounts or for customers, including, without limitation, affiliates of the Fund.

In the event of a system failure or other interruption, including disruptions at market makers or Authorized Participants, orders to purchase or redeem Creation Units either may not be executed according to the Fund’s instructions or may not be executed at all, or the Fund may not be able to place or change orders.

To the extent the Fund engages in in-kind transactions, the Fund intends to comply with the U.S. federal securities laws in accepting securities for deposit and satisfying redemptions with redemption securities by, among other means, assuring that any securities accepted for deposit and any securities used to satisfy redemption requests will be sold in transactions that would be exempt from registration under the Securities Act of 1933, as amended (the “1933 Act”). Further, an Authorized Participant that is not a “qualified institutional buyer,” as such term is defined in Rule 144A under the 1933 Act, will not be able to receive restricted securities eligible for resale under Rule 144A.

Creations and redemptions must be made through a firm that is either a member of the Continuous Net Settlement System of the National Securities Clearing Corporation or a DTC participant that has executed an agreement with the Distributor with respect to creations and redemptions of Creation Unit aggregations. Information about the procedures regarding creation and redemption of Creation Units (including the cut-off times for receipt of creation and redemption orders) is included in the Fund’s SAI.

Because new shares may be created and issued on an ongoing basis, at any point during the life of the Fund a “distribution,” as such term is used in the 1933 Act, may be occurring. Broker-dealers and other persons are cautioned that some activities on their part may, depending on the circumstances, result in their being deemed participants in a distribution in a manner that could render them statutory underwriters subject to the prospectus delivery and liability provisions of the 1933 Act. Any determination of whether one is an underwriter must take into account all the relevant facts and circumstances of each particular case.

Broker-dealers should also note that dealers who are not “underwriters” but are participating in a distribution (as contrasted to ordinary secondary transactions), and thus dealing with shares that are part of an “unsold allotment” within the meaning of Section 4(a)(3)(C) of the 1933 Act, would be unable to take advantage of the prospectus delivery exemption provided by Section 4(a)(3) of the 1933 Act. For delivery of prospectuses to exchange members, the prospectus delivery mechanism of Rule 153 under the 1933 Act is available only with respect to transactions on a national securities exchange.

Householding. Householding is an option available to certain Fund investors. Householding is a method of delivery, based on the preference of the individual investor, in which a single copy of certain shareholder documents can be delivered to investors who share the same address, even if their accounts are registered under different names. Please contact your broker-dealer if you are interested in enrolling in householding and receiving a single copy of prospectuses and other shareholder documents, or if you are currently enrolled in householding and wish to change your householding status.

The Distributor or its agent distributes Creation Units for the Fund on an agency basis. The Distributor does not maintain a secondary market in shares of the Fund. The Distributor has no role in determining the policies of the Fund or the securities that are purchased or sold by the Fund. The Distributor’s principal address is 50 Hudson Yards, New York, NY 10001.

BFA or its affiliates make payments to broker-dealers, registered investment advisers, banks or other intermediaries (together, “intermediaries”) related to marketing activities and presentations, educational training programs, conferences, the development of technology platforms and reporting systems, data provision services, or their making shares of the Fund and certain other BFA-advised ETFs available to their customers generally and in certain investment programs. Such payments, which may be significant to the intermediary, are not made by the Fund. Rather, such payments are made by BFA or its affiliates from their own resources, which come directly or indirectly in part from fees paid by the BFA-advised ETFs. Payments of this type are sometimes referred to as revenue-sharing payments. A financial intermediary may make decisions about which investment options it recommends or makes available, or the level of services provided, to its customers based on the payments or other financial incentives it is eligible to receive. Therefore, such payments or other financial incentives offered or made to an intermediary create conflicts of interest between the intermediary and its customers and may cause the intermediary to recommend the Fund or other BFA-advised ETFs over another investment. More information regarding these payments is contained in the Fund’s SAI. Please contact your salesperson or other investment professional for more information regarding any such payments his or her firm may receive from BFA or its affiliates.

The financial highlights table is intended to help investors understand the Fund’s financial performance since inception. Certain information reflects financial results for a single share of the Fund. The total returns in the table represent the rate that an investor would have earned (or lost) on an investment in the Fund, assuming reinvestment of all dividends and distributions. This information has been audited by PricewaterhouseCoopers LLP, whose report is included, along with the Fund’s financial statements, in the Fund’s Annual Report (available upon request).

Shares of the Fund are not sponsored, endorsed or promoted by NYSE Arca. NYSE Arca makes no representation or warranty, express or implied, to the owners of shares of the Fund or any member of the public regarding the ability of the Fund to achieve its investment objectives. NYSE Arca is not responsible for, nor has it participated in, the determination of the Fund’s investments, nor in the determination of the timing of, prices of, or quantities of shares of the Fund to be issued, nor in the determination or calculation of the equation by which shares are redeemable. NYSE Arca has no obligation or liability to owners of the shares of the Fund in connection with the administration, marketing or trading of shares of the Fund.

Without limiting any of the foregoing, in no event shall NYSE Arca have any liability for any direct, indirect, special, punitive, consequential or any other damages (including lost profits) even if notified of the possibility of such damages.

Information on the Fund’s net asset value, market price, premiums and discounts, and bid-ask spreads can be found at www.blackrock.com.

Copies of the Prospectus, SAI and other information can be found on our website at www.blackrock.com. For more information about the Fund, you may request a copy of the SAI. The SAI provides detailed information about the Fund and is incorporated by reference into this Prospectus. This means that the SAI, for legal purposes, is a part of this Prospectus.

If you have any questions about the Trust or shares of the Fund or you wish to obtain the SAI free of charge, please:

Reports and other information about the Fund are available on the EDGAR database on the SEC’s website at www.sec.gov, and copies of this information may be obtained, after paying a duplicating fee, by electronic request at the following e-mail address: publicinfo@sec.gov.

No person is authorized to give any information or to make any representations about the Fund and its shares not contained in this Prospectus and you should not rely on any other information. Read and keep this Prospectus for future reference.



Fund Overview of BlackRock Flexible Income ETF			S-1

More Information About the Fund			10

A Further Discussion of Principal Risks			11

A Further Discussion of Other Risks			22

Portfolio Holdings Information			23

Management			23

Shareholder Information			25

Distribution			30

Financial Highlights			31

Disclaimers			32


	BlackRock Flexible Income ETF
(For a share outstanding throughout the period)	Period From 05/19/23^(a) to 07/31/23
Net asset value, beginning of period	$	50.00
Net investment income^(b)		0.54
Net realized and unrealized gain^(c)		0.52
Net increase from investment operations		1.06
Distributions from net investment income^(d)		(0.25	)
Net asset value, end of period	$	50.81
Total Return^(e)
Based on net asset value		2.14	%^(f)
Ratios to Average Net Assets^(g)
Total expenses		0.50	%^(h)
Total expenses after fees waived		0.37	%^(h)
Net investment income		5.39	%^(h)
Supplemental Data
Net assets, end of period (000)	$	129,574
Portfolio turnover rate^(i)(j)		54	%
^(a) Commencement of operations. ^(b) Based on average shares outstanding. ^(c) The amounts reported for a share outstanding may not accord with the change in aggregate gains and losses in securities for the fiscal period due to the timing of capital share transactions in relation to the fluctuating market values of the Fund’s underlying securities. ^(d) Distributions for annual periods determined in accordance with U.S. federal income tax regulations. ^(e) Where applicable, assumes the reinvestment of distributions. ^(f) Not annualized. ^(g) Excludes fees and expenses incurred indirectly as a result of investments in underlying funds. ^(h) Annualized. ⁽ⁱ⁾ Includes mortgage dollar roll transactions (“MDRs”). Excluding MDRs, the portfolio turnover rate would have been 45%. ^(j) Portfolio turnover rate excludes in-kind transactions.


Call:		1-800-474-2737 (toll free)
Write:		c/o BlackRock Investments, LLC
		1 University Square Drive, Princeton, NJ 08540

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		NOVEMBER 28, 2023, as amended December 6, 2023