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. From inception (September 29, 2020) to the most recent fiscal year end, the Fund’s portfolio turnover rate was 0.50% of the average value of its portfolio.

Principal Investment Strategies

Under normal market conditions, the Fund will invest at least 80% of its net assets plus any borrowings for investment purposes in equity securities issued by mid- and small-capitalization companies that BFA believes have above-average earnings growth potential.

Equity securities include common stocks, preferred stocks, convertible securities, warrants and depositary receipts, though the Fund seeks to buy primarily common stock. Although universal definitions of small-capitalization companies and mid-capitalization companies do not exist, the Fund generally defines small-capitalization and mid-capitalization companies as those companies with market capitalizations, at the time of the Fund’s investment, comparable in size to the companies in the Russell 2500^™ Growth Index (between $5,516,100 and $34,351,511,400 as of November 5, 2021). In the future, the Fund may define small- or

mid-capitalization companies using a different index or classification system.

In selecting investments for the Fund, BFA focuses on equity securities of small- and mid-capitalization growth companies that are “innovative.” These are companies that have introduced, or are seeking to introduce, a new product or service that potentially changes the marketplace. In evaluating innovative companies, BFA seeks to identify, using its own internal research and analysis, companies capitalizing on innovation or that are enabling the further development of the theme of innovation in the markets in which they operate.

The Fund may invest in shares of companies through initial public offerings (“IPOs”). The Fund may invest up to 25% of its assets in securities of foreign companies, including companies located in emerging markets. Foreign securities in which the Fund may invest may be U.S. dollar-denominated or non-U.S. dollar-denominated.

The Fund may also invest in securities of other open- or closed-end investment companies, subject to applicable regulatory limits, that invest primarily in securities of the types in which the Fund may invest directly. The Fund classifies its investments in such investment companies as “equity securities” for purposes of its investment policies based upon such investment companies’ stated investment objectives, policies and restrictions.

During temporary defensive periods (i.e., in response to adverse market, economic or political conditions), the Fund may invest up to 100% of its total assets in liquid, short-term

 

investments, including high quality, short-term securities. The Fund may not achieve its investment objectives under these circumstances. BFA’s determination that it is temporarily unable to follow the Fund’s investment strategy or that it is impractical to do so will generally occur only in situations in which a market disruption event has occurred and where trading in the securities selected through application of the Fund’s investment strategy is extremely limited or absent.

The Fund may lend securities representing up to one-third of the value of the Fund’s total assets (including the value of the collateral received).

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 objective. Unlike many exchange-traded funds (“ETFs”), the Fund is not an index-based ETF. The order of the below risk factors does not indicate the significance of any particular risk factor.

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 the 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 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.

Concentration Risk. The Fund may be susceptible to loss due to adverse events that affect the Fund’s investments more than the market as a whole, to the extent that the Fund’s

 

investments are concentrated in the securities and/or other assets of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class.

Convertible Securities Risk. The market price of a convertible security generally tends to behave like that of a regular debt security; that is, if market interest rates rise, the value of a convertible security usually falls. In addition, convertible securities are subject to the risk that the issuer will not be able to pay interest, principal or dividends when due, and their market value may change based on changes in the issuer’s credit rating or the market’s perception of the issuer’s creditworthiness. Because a convertible security derives a portion of its value from the common stock into which it may be converted, a convertible security is also subject to the same types of market and issuer risks that apply to the underlying common stock, including the potential for increased volatility in the price of the convertible security.

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.

Depositary Receipts Risk. The Fund will invest in stocks of foreign corporations. The Fund’s investment in such stocks will be in the form of depositary receipts including American Depositary Receipts (“ADRs”) and Global Depositary Receipts (“GDRs”). While the use of ADRs and GDRs, which are traded on exchanges and represent an ownership in a foreign security, provide an alternative to directly purchasing the underlying foreign securities in their respective markets and currencies, investments in ADRs and GDRs continue to be subject to many of the risks associated with investing directly in foreign securities, including political, economic, and currency risk.

Equity Securities Risk. Equity securities are subject to changes in value, and their values may be more volatile than those of other asset classes. Common stocks generally subject their holders to more risks than preferred stocks and debt securities because common stockholders’ claims are subordinated to those of holders of preferred stocks and debt securities upon the bankruptcy of the issuer.

Growth Securities Risk. The Fund invests in growth securities, which may be more volatile than other types of investments, may perform differently than the market as a whole and may underperform when compared to securities with different investment

 

parameters. Companies with forecasted higher levels of sales growth relative to U.S. domestic capital spending may not in fact experience growth or higher growth relative to U.S. capital expenditures. Under certain market conditions, growth securities have performed better during the later stages of economic recovery (although there is no guarantee that they will continue to do so). Therefore, growth securities may go in and out of favor over time.

Healthcare Sector Risk. The profitability of companies in the healthcare sector, including healthcare equipment and services companies, may be affected by government regulations and government healthcare programs, increases or decreases in the cost of medical products and services, an increased emphasis on outpatient services, demand for medical products and services and product liability claims, among other factors. Many healthcare companies are heavily dependent on patent protection, and the expiration of a company’s patent may adversely affect that company’s profitability. Healthcare companies are subject to competitive forces that may result in price discounting, and may be thinly capitalized and susceptible to product obsolescence.

High Portfolio Turnover Risk. 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, as well as possible increased taxable distributions.

Infectious Illness Risk. An outbreak of an infectious respiratory illness, COVID-19, caused by a novel coronavirus has resulted in travel restrictions, disruption of healthcare systems, prolonged quarantines, cancellations, supply chain disruptions, lower consumer demand, layoffs, ratings downgrades, defaults and other significant economic impacts. Certain markets have experienced temporary closures, extreme volatility, severe losses, reduced liquidity and increased trading costs. These events will have an impact on the Fund and its investments and could impact the Fund’s ability to purchase or sell securities or cause increased premiums or discounts to the Fund’s NAV. Other infectious illness outbreaks in the future may result in similar impacts.

Industrials Sector Risk. Companies in the industrials sector may be adversely affected by changes in the supply of and demand for products and services, product obsolescence, claims for environmental damage or product liability and changes in general economic conditions, among other factors.

Information Technology Sector Risk. Information technology companies face intense competition and potentially rapid product obsolescence. They are also heavily dependent on intellectual property rights and may be adversely affected by the loss or impairment of those rights. Companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject

 

to adverse government or regulatory action. Companies in the software industry may be adversely affected by, among other things, the decline or fluctuation of subscription renewal rates for their products and services and actual or perceived vulnerabilities in their products or services.

Innovative Securities Risk. There can be no assurance that a company identified as innovative by BFA will ultimately introduce a new product or service or that such product or service may not be significantly delayed.

Investment in Other Investment Companies Risk. As with other investments, investments in other investment companies, including ETFs, are subject to market and selection risk. In addition, if the Fund acquires shares of investment companies, including ones affiliated with the Fund, shareholders bear both their proportionate share of expenses in the Fund (including management and advisory fees) and, indirectly, the expenses of the investment companies (to the extent not offset by BFA through waivers). 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. Changes in the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline.

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, the spread of infectious illness or other public health issues like pandemics or epidemics, recessions, 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.

Mid-Capitalization Companies Risk. Compared to large-capitalization companies, mid-capitalization companies may be less stable and more susceptible to adverse developments. In addition, the securities of mid-capitalization companies may be more volatile and less liquid than those of large-capitalization companies.

“New Issues” Risk. “New issues” are IPOs of equity securities. Securities issued in IPOs have no trading history, and information about the companies may be available for very limited periods. In addition, the prices of securities sold in IPOs may be highly volatile or may decline shortly after the IPO.

Non-Diversification Risk. 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 depend on the performance of a small number of issuers.

Non-U.S. Securities Risk. Investments in the securities of non-U.S. issuers are subject to the risks associated with investing in those non-U.S. markets, such as heightened risks of inflation or nationalization. The Fund may lose money due to political, economic and geographic events affecting issuers of non-U.S. securities or non-U.S. markets. In addition, non-U.S. securities markets 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.

Operational Risk. The Fund is exposed to operational risks arising from a number of factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third parties, failed or inadequate processes and technology or systems failures. The Fund and BFA seek to reduce these operational risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate to address significant operational risks.

Preferred Stock Risk. Preferred stocks are subject not only to issuer-specific and market risks generally applicable to equity securities, but also risks associated with fixed-income securities, such as interest rate risk. A company’s preferred stock, which may pay fixed or variable rates of return, generally pays dividends only after the company makes required payments to creditors, including vendors, depositors, counterparties, holders of its bonds and other fixed-income securities. As a result, the value of a company’s preferred stock will react more strongly than bonds and other debt to actual or perceived changes in the company’s financial condition or prospects. Preferred stock may be less liquid than many other types of securities, such as common stock, and generally has limited or no voting rights. Preferred stock generally does not reflect the performance of a company as directly as the company’s common stock. In

 

addition, preferred stock is subject to the risks that a company may defer or not pay dividends, and, in certain situations, may call or redeem its preferred stock or convert it to common stock. An issuer may decide to call its outstanding preferred stock in various environments based on its assessment of the relative cost of capital across the company’s capital structure. A market-wide increase in preferred stock being called may reduce the aggregate size of the preferred stock universe and the number of issuers with preferred stock outstanding. To the extent that the Fund invests a substantial portion of its assets in convertible preferred stocks, declining common stock values may also cause the value of the Fund’s investments to decline.

Risk of Investing in Emerging Markets. Investments in emerging markets 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, political turmoil and 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. Although the Fund is actively managed, investments are not generally selected based on investor protection limitations or differences in the quality of financial reporting and available oversight mechanisms.

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.

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 if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund.

Small-Capitalization Companies Risk. Compared to mid- and large-capitalization companies, small-capitalization companies may be less stable and more susceptible to adverse developments. In addition, the securities of small-capitalization companies may be more volatile and less liquid than those of mid- and large-capitalization companies.

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.

Warrants Risk. If the price of the underlying stock does not rise above the exercise price before the warrant expires, the warrant generally expires without any value and the Fund will lose any amount it paid for the warrant. Thus, investments in warrants may involve substantially more risk than investments in common stock. Warrants may trade in the same markets as their underlying stock; however, the price of the warrant does not necessarily move with the price of the underlying stock.

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 Russell 2500^™ Growth Index.

Management

Investment Adviser. BlackRock Fund Advisors.

Portfolio Managers. Phil Ruvinsky, CFA, and William Broadbent (the “Portfolio Managers”) are jointly and primarily responsible for the day-to-day management of the Fund. Each Portfolio Manager supervises a portfolio management team. Messrs. Ruvinsky and Broadbent have been Portfolio Managers of the Fund since September 2020.

Purchase and Sale of Fund Shares

This 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 you 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 taxed 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.