August 31, 2018

2018 Prospectus

►	iShares Cohen & Steers REIT ETF | ICF | CBOE BZX

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

Table of Contents

“Cohen & Steers” and “Cohen & Steers Realty Majors Index” are trademarks of Cohen & Steers Capital Management, Inc. and have been licensed for use for certain purposes by BlackRock Fund Advisors or its affiliates. iShares ^® and BlackRock ^® are registered trademarks of BlackRock Fund Advisors and its affiliates. The Fund is not sponsored, endorsed, sold or promoted by Cohen & Steers Capital Management, Inc., and Cohen & Steers Capital Management, Inc. makes no representation regarding the advisability of investing in the Fund.

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Investment Objective

The iShares Cohen & Steers REIT ETF (the “Fund”) seeks to track the investment results of an index composed of U.S. real estate investment trusts (“REITs”).

Fees and Expenses

The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (the “Investment Advisory Agreement”) provides that BFA will pay all operating 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.

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		Distribution and Service (12b-1) Fees		Other Expenses		Total Annual Fund Operating Expenses
0.34%		None		None		0.34%

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		5 Years		10 Years
$35		$109		$191		$431

Management

Investment Adviser. BlackRock Fund Advisors.

Portfolio Managers. Rachel Aguirre, Diane Hsiung, Jennifer Hsui, Alan Mason, Greg Savage and Amy Whitelaw (the “Portfolio Managers”) are primarily responsible for the day-to-day management of the Fund. Each Portfolio Manager supervises a portfolio management team. Ms. Aguirre, Ms. Hsiung, Ms. Hsui, Mr. Mason, Mr. Savage and Ms. Whitelaw have been Portfolio Managers of the Fund since 2018, 2008, 2012, 2016, 2008 and 2018, respectively.

Purchase and Sale of Fund Shares

The Fund is an exchange-traded fund (commonly referred to as an “ETF”). Individual shares of the Fund are listed on a national securities exchange. Most investors will buy and sell shares of the Fund through a broker-dealer. The price of Fund shares is based on market price, and 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). The Fund will only issue or redeem shares that have been aggregated into blocks of 50,000 shares or multiples thereof (“Creation Units”) to Authorized Participants who have entered into agreements with the Fund's distributor. The Fund generally will issue or redeem Creation Units in return for a designated portfolio of securities (and an amount of cash) that the Fund specifies each day.

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More Information About the Fund

This Prospectus contains important information about investing in the Fund. Please read this Prospectus carefully before you make any investment decisions. Additional information regarding the Fund is available at www.iShares.com.

BFA is the investment adviser to the Fund. Shares of the Fund are listed for trading on Cboe BZX Exchange, Inc. (“Cboe BZX”) (formerly known as BATS Exchange, Inc.). The market price for a share of the Fund may be different from the Fund’s most recent NAV.

ETFs are funds that trade like other publicly-traded securities. The Fund is designed to track an index. Similar to shares of an index mutual fund, each share of the Fund represents an ownership interest in an underlying portfolio of securities and other instruments intended to track a market index. 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 Creation Unit increments. 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 invests in a particular segment of the securities markets and seeks to track the performance of a securities index that may not be representative of the market as a whole. The Fund is designed to be used as part of broader asset allocation strategies. Accordingly, an investment in the Fund should not constitute a complete investment program.

An index is a financial calculation, based on a grouping of financial instruments, and is not an investment product, while the Fund is an actual investment portfolio. The performance of the Fund and the Underlying Index may vary for a number of reasons, including transaction costs, non-U.S. currency valuations, asset valuations, corporate actions (such as mergers and spin-offs), timing variances and differences between the Fund’s portfolio and the Underlying Index resulting from the Fund's use of representative sampling or from legal restrictions (such as diversification requirements) that apply to the Fund but not to the Underlying Index. From time to time, the Index Provider may make changes to the methodology or other adjustments to the Underlying Index. Unless otherwise determined by BFA, any such change or adjustment will be reflected in the calculation of the Underlying Index performance on a going-forward basis after the effective date of such change or adjustment. Therefore, the Underlying Index performance shown for periods prior to the effective date of any such change or adjustment will generally not be recalculated or restated to reflect such change or adjustment.

“Tracking error” is the divergence of the performance (return) of the Fund's portfolio from that of the Underlying Index. BFA expects that, over time, the Fund’s tracking error will not exceed 5%. Because the Fund uses a representative sampling indexing strategy, it can be expected to have a larger tracking error than if it used a replication

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indexing strategy. “Replication” is an indexing strategy in which a fund invests in substantially all of the securities in its underlying index in approximately the same proportions as in the underlying index.

Under continuous listing standards adopted by the Fund's listing exchange, which went into effect on January 1, 2018, the Fund is required to confirm on an ongoing basis that the components of the Underlying Index satisfy the applicable listing requirements. In the event that the Underlying Index does not comply with the applicable listing requirements, the Fund is required to rectify such non-compliance by requesting that the Index Provider modify the Underlying Index, adopting a new underlying index, or obtaining relief from the SEC. Failure to rectify such non-compliance may result in the Fund being delisted by the listing exchange.

An investment in the Fund is not a bank deposit and it is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency, BFA or any of its affiliates.

The Fund's investment objective and the Underlying Index may be changed without shareholder approval.

A Further Discussion of Principal Risks

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 objective. You could lose all or part of your investment in the Fund, and the Fund could underperform other investments.

Asset Class Risk. The securities and other assets in the Underlying Index or in the Fund’s portfolio may underperform in comparison to other securities or indexes that track other countries, groups of countries, regions, industries, groups of industries, markets, asset classes or sectors. Various types of securities, currencies and indexes 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. This may cause the Fund to underperform other investment vehicles that invest in different asset classes.

Authorized Participant Concentration Risk. Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. 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.

Concentration Risk. The Fund may be susceptible to an increased risk of loss, including losses 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 of a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. The Fund may be more

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adversely affected by the underperformance of those securities, may experience increased price volatility and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting those securities than a fund that does not concentrate its investments.

Cyber Security Risk. With the increased use of technologies such as the internet to conduct business, the Fund, Authorized Participants, service providers and the relevant listing exchange are susceptible to operational, information security and related “cyber” risks both directly and through their service providers. Similar types of cyber security risks are also present for issuers of securities in which the Fund invests, which could result in material adverse consequences for such issuers and may cause the Fund’s investment in such portfolio companies to lose value. Unlike many other types of risks faced by the Fund, these risks typically are not covered by insurance. In general, cyber incidents can result from deliberate attacks or unintentional events. Cyber incidents include, but are not limited to, gaining unauthorized access to digital systems ( e.g. , through “hacking” or malicious software coding) for purposes of misappropriating assets or sensitive information, corrupting data, or causing operational disruption. Cyber attacks may also be carried out in a manner that does not require gaining unauthorized access, such as causing denial-of-service attacks on websites ( i.e. , efforts to make network services unavailable to intended users). Cyber security failures by or breaches of the systems of the Fund’s adviser, distributor and other service providers (including, but not limited to, index providers, fund accountants, custodians, transfer agents and administrators), market makers, Authorized Participants 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, cyber attacks may render records of Fund assets and transactions, shareholder ownership of Fund shares, and other data integral to the functioning of the Fund inaccessible or 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 attacks, there are inherent limitations in such plans and systems, including the possibility that certain risks have not been identified and that prevention and remediation efforts will not be successful. Furthermore, the Fund cannot control the cyber security plans and systems put in place by service providers to the Fund, issuers in which the Fund invests, the Index Provider, market makers or Authorized Participants. The Fund and its shareholders could be negatively impacted as a result.

Equity Securities Risk. The Fund invests in equity securities, which are subject to changes in value that may be attributable to market perception of a particular issuer or to general stock market fluctuations that affect all issuers. Investments in equity securities may be more volatile than investments in other asset classes. The Underlying Index is comprised of common stocks, which generally subject their

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holders to more risks than holders of 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.

Index-Related Risk. The Fund seeks to achieve a return that corresponds generally to the price and yield performance, before fees and expenses, of the Underlying Index as published by the Index Provider. There is no assurance that the Index Provider or any agents that may act on its behalf will compile the Underlying Index accurately, or that the Underlying Index will be determined, composed or calculated accurately. While the Index Provider provides descriptions of what the Underlying Index is designed to achieve, neither the Index Provider nor its agents provide any warranty or accept any liability in relation to the quality, accuracy or completeness of the Underlying Index or its related data, and they do not guarantee that the Underlying Index will be in line with the Index Provider’s methodology. BFA’s mandate as described in this Prospectus is to manage the Fund consistently with the Underlying Index provided by the Index Provider to BFA. BFA does not provide any warranty or guarantee against the Index Provider’s or any agent’s errors. Errors in respect of the quality, accuracy and completeness of the data used to compile the Underlying Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the indices are less commonly used as benchmarks by funds or managers. Therefore, gains, losses or costs associated with errors of the Index Provider or its agents will generally be borne by the Fund and its shareholders. For example, during a period where the Underlying Index contains incorrect constituents, the Fund would have market exposure to such constituents and would be underexposed to the Underlying Index’s other constituents. Such errors may negatively or positively impact the Fund and its shareholders.

Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Underlying Index in order, for example, to correct an error in the selection of index constituents. When the Underlying Index is rebalanced and the Fund in turn rebalances its portfolio to attempt to increase the correlation between the Fund’s portfolio and the Underlying Index, any transaction costs and market exposure arising from such portfolio rebalancing will be borne directly by the Fund and its shareholders. Unscheduled rebalances to the Underlying Index may expose the Fund to additional tracking error risk, which is the risk that the Fund's returns may not track those of the Underlying Index. Therefore, errors and additional ad hoc rebalances carried out by the Index Provider or its agents to the Underlying Index may increase the costs to and the tracking error risk of the Fund.

Issuer Risk. The performance of the Fund depends on the performance of individual securities to which the Fund has exposure. 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. Issuers may, in times of distress or at their own discretion, decide to reduce or eliminate dividends, which may also cause their stock prices to decline. An

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issuer may also be subject to risks associated with the countries, states and regions in which the issuer resides, invests, sells products, or otherwise conducts operations.

Large-Capitalization Companies Risk. Large-capitalization companies may be less able than smaller capitalization companies to adapt to changing market conditions. Large-capitalization companies may be more mature and subject to more limited growth potential compared with smaller capitalization companies. During different market cycles, the performance of large-capitalization companies has trailed the overall performance of the broader securities markets.

Management Risk. The Fund may not fully replicate the Underlying Index and may hold securities not included in the Underlying Index. As a result, the Fund is subject to the risk that BFA’s investment strategy, the implementation of which is subject to a number of constraints, may not produce the intended results.

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 security or other asset may decline due to changes in general market conditions, economic trends or events that are not specifically related to the issuer of the security or other asset, or factors that affect a particular issuer or issuers, country, group of countries, region, market, industry, group of industries, sector or asset class. During a general market downturn, multiple asset classes may be negatively affected. Changes in market conditions and interest rates generally do not have the same impact on all types of securities and instruments.

Market Trading Risk

Absence of Active Market. Although shares of the Fund are listed for trading on one or more stock exchanges, there can be no assurance that an active trading market for such shares will develop or be maintained by market makers or Authorized Participants.

Risk of Secondary Listings. The Fund's shares may be listed or traded on U.S. and non-U.S. stock exchanges other than the U.S. stock exchange where the Fund's primary listing is maintained, and may otherwise be made available to non-U.S. investors through funds or structured investment vehicles similar to depositary receipts. There can be no assurance that the Fund’s shares will continue to trade on any such stock exchange or in any market or that the Fund’s shares will continue to meet the requirements for listing or trading on any exchange or in any market. The Fund's shares may be less actively traded in certain markets than in others, and investors are subject to the execution and settlement risks and market standards of the market where they or their broker direct their trades for execution. Certain information available to investors who trade Fund shares on a U.S. stock exchange during regular U.S. market hours may not be available to investors who trade in other markets, which may result in secondary market prices in such markets being less efficient.

Secondary Market Trading Risk. Shares of the Fund may trade in the secondary market at times when the Fund does not accept orders to purchase or redeem shares. At such times, shares may trade in the secondary market with more significant premiums or discounts than might be experienced at times when the Fund accepts purchase and redemption orders.

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Secondary market trading in Fund shares may be halted by a stock exchange because of market conditions or for other reasons. In addition, trading in Fund shares on a stock exchange or in any market may be subject to trading halts caused by extraordinary market volatility pursuant to “circuit breaker” rules on the stock exchange or market.

Shares of the Fund, similar to shares of other issuers listed on a stock exchange, may be sold short and are therefore subject to the risk of increased volatility and price decreases associated with being sold short.

Shares of the Fund May Trade at Prices Other Than NAV. Shares of the Fund trade on stock exchanges at prices at, above or below the Fund’s most recent NAV. The NAV of the Fund is calculated at the end of each business day and fluctuates with changes in the market value of the Fund’s holdings. The trading price of the Fund's shares fluctuates continuously throughout trading hours based on both market supply of and demand for Fund shares and the underlying value of the Fund's portfolio holdings or NAV. As a result, the trading prices of the Fund’s shares may deviate significantly from NAV during periods of market volatility. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV . However, because shares can be created and redeemed in Creation Units at NAV, BFA believes that large discounts or premiums to the NAV of the Fund are not likely to be sustained over the long term (unlike shares of many closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their NAVs). While the creation/redemption feature is designed to make it more likely that the Fund’s shares normally will trade on stock exchanges at prices close to the Fund’s next calculated NAV, exchange prices are not expected to correlate exactly with the Fund's NAV due to timing reasons, supply and demand imbalances and other factors. In addition, disruptions to creations and redemptions, including disruptions at market makers, Authorized Participants, or other market participants, and during periods of significant market volatility, may result in trading prices for shares of the Fund that differ significantly from its NAV. Authorized Participants may be less willing to create or redeem Fund shares if there is a lack of an active market for such shares or its underlying investments, which may contribute to the Fund’s shares trading at a premium or discount to NAV.

Costs of Buying or Selling Fund Shares. Buying or selling Fund shares on an exchange involves two types of costs that apply to all securities transactions. When buying or selling shares of the Fund through a broker, you will likely incur a brokerage commission and other charges. In addition, you may incur the cost of the “spread”; that is, the difference between what investors are willing to pay for Fund shares (the “bid” price) and the price at which they are willing to sell Fund shares (the “ask” price). The spread, which varies over time for shares of the Fund based on trading volume and market liquidity, is generally narrower if the Fund has more trading volume and market liquidity and wider if the Fund has less trading volume and market liquidity. In addition, increased market volatility may cause wider spreads. There may also be regulatory and other charges that are incurred as a result of trading activity. Because of the costs inherent in buying or selling Fund shares, frequent trading may detract significantly from investment results and an investment in Fund shares may not be

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advisable for investors who anticipate regularly making small investments through a brokerage account.

Mid-Capitalization Companies Risk. Stock prices of mid-capitalization companies may be more volatile than those of large-capitalization companies and, therefore, the Fund’s share price may be more volatile than those of funds that invest a larger percentage of their assets in stocks issued by large-capitalization companies. Stock prices of mid-capitalization companies are also more vulnerable than those of large-capitalization companies to adverse business or economic developments, and the stocks of mid-capitalization companies may be less liquid, making it difficult for the Fund to buy and sell shares of mid-capitalization companies. In addition, mid-capitalization companies generally have less diverse product lines than large-capitalization companies and are more susceptible to adverse developments.

Non-Diversification Risk. The Fund is classified as “non-diversified.” This means that 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 may be more susceptible to the risks associated with these particular issuers or to a single economic, political or regulatory occurrence affecting these issuers.

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.

Passive Investment Risk. The Fund is not actively managed and may be affected by a general decline in market segments related to the Underlying Index. The Fund invests in securities included in, or representative of, the Underlying Index, regardless of their investment merits. BFA generally does not attempt to invest the Fund's assets in defensive positions under any market conditions, including declining markets.

Real Estate Investment Risk. The Fund invests in Real Estate Companies, such as REITs or real estate holding and operating companies, which expose investors to the risks of owning real estate directly, as well as to risks that relate specifically to the way in which Real Estate Companies are organized and operated. Real estate is highly sensitive to general and local economic conditions and developments and is characterized by intense competition and periodic overbuilding. Many Real Estate Companies, including REITs, utilize leverage (and some may be highly leveraged), which increases investment risk and the risk normally associated with debt financing, and could potentially increase the Fund’s losses. Rising interest rates could result in higher costs of capital for Real Estate Companies, which could negatively affect a Real Estate Company's ability to meet its payment obligations or its financing activity, and could decrease the market prices for REITs and for properties held by such REITs. The U.S. residential and commercial real estate markets may, in the future, experience and have, in the past, experienced a decline in value, with certain regions experiencing significant losses in property values. Exposure to such real estate may adversely affect Fund performance. In addition, to the extent a Real Estate Company has its own

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expenses, the Fund (and indirectly, its shareholders) will bear its proportionate share of such expenses.

Concentration Risk . Real Estate Companies may own a limited number of properties and concentrate their investments in a particular geographic region, industry or property type. Economic downturns affecting a particular region, industry or property type may lead to a high volume of defaults within a short period.

Equity REITs Risk. Certain REITs may make direct investments in real estate. These REITs are often referred to as “Equity REITs.” Equity REITs invest primarily in real properties and may earn rental income from leasing those properties. Equity REITs may also realize gains or losses from the sale of properties. Equity REITs will be affected by conditions in the real estate rental market and by changes in the value of the properties they own. A decline in rental income may occur because of extended vacancies, limitations on rents, the failure to collect rents, increased competition from other properties or poor management. Equity REITs also can be affected by rising interest rates. Rising interest rates may cause investors to demand a high annual yield from future distributions that, in turn, could decrease the market prices for such REITs and for the properties held by such REITs. In addition, rising interest rates also increase the costs of obtaining financing for real estate projects. Because many real estate projects are dependent upon receiving financing, this could cause the value of the Equity REITs in which the Fund invests to decline.

Interest Rate Risk . Rising interest rates could result in higher costs of capital for Real Estate Companies, which could negatively affect a Real Estate Company’s ability to meet its payment obligations. Declining interest rates could result in increased prepayment on loans and require redeployment of capital in less desirable investments.

Leverage Risk . Real Estate Companies may use leverage (and some may be highly leveraged), which increases investment risk and the risks normally associated with debt financing and could adversely affect a Real Estate Company’s operations and market value in periods of rising interest rates. Financial covenants related to a Real Estate Company’s leveraging may affect the ability of the Real Estate Company to operate effectively. In addition, investments may be subject to defaults by borrowers and tenants. Leveraging may also increase repayment risk.

Liquidity Risk . Investing in Real Estate Companies may involve risks similar to those associated with investing in small-capitalization companies. Real Estate Company securities may be volatile. There may be less trading in Real Estate Company shares, which means that purchase and sale transactions in those shares could have a magnified impact on share price, resulting in abrupt or erratic price fluctuations. In addition, real estate is relatively illiquid and, therefore, a Real Estate Company may have a limited ability to vary or liquidate its investments in properties in response to changes in economic or other conditions.

Loan Foreclosure Risk. Real Estate Companies may foreclose on loans that the Real Estate Company originated and/or acquired. Foreclosure may generate negative publicity for the underlying property that affects its market value. In addition to length

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and expense, the validity of the terms of the applicable loan may not be enforced in foreclosure proceedings.

Operational Risk . Real Estate Companies are dependent upon management skills and may have limited financial resources. Real Estate Companies are generally not diversified and may be subject to heavy cash flow dependency, default by borrowers and self-liquidation. In addition, transactions between Real Estate Companies and their affiliates may be subject to conflicts of interest, which may adversely affect a Real Estate Company’s shareholders. A Real Estate Company may also have joint ventures in certain of its properties and, consequently, its ability to control decisions relating to such properties may be limited.

Property Risk . Real Estate Companies may be subject to risks relating to functional obsolescence or reduced desirability of properties; extended vacancies due to economic conditions and tenant bankruptcies; property damage due to events such as earthquakes, hurricanes, tornadoes, rodent, insect or disease infestations and terrorist acts; eminent domain seizures; and casualty or condemnation losses. Real estate income and values also may be greatly affected by demographic trends, such as population shifts, changing tastes and values, increasing vacancies or declining rents resulting from legal, cultural, technological, global or local economic developments and changes in tax law.

Regulatory Risk . Real estate income and values may be adversely affected by applicable domestic and foreign laws (including tax laws). Government actions, such as tax increases, zoning law changes, reduced funding for schools, parks, garbage collection and other public services or environmental regulations also may have a major impact on real estate income and values.

Repayment Risk. The prices of Real Estate Company securities may drop because of the failure of borrowers to repay their loans, poor management, or the inability to obtain financing either on favorable terms or at all. If the properties in which Real Estate Companies invest do not generate sufficient income to meet operating expenses, including, where applicable, debt service, ground lease payments, tenant improvements, third-party leasing commissions and other capital expenditures, the income and ability of the Real Estate Companies to make payments of interest and principal on their loans will be adversely affected.

U.S. Tax Risk . Certain U.S. Real Estate Companies are subject to special U.S. federal tax requirements. A REIT that fails to comply with such tax requirements may be subject to U.S. federal income taxation, which may affect the value of the REIT and the characterization of the REIT's distributions. The U.S. federal tax requirement that a REIT distributes substantially all of its net income to its shareholders may result in the REIT having insufficient capital for future expenditures. A REIT that successfully maintains its qualification may still become subject to U.S. federal, state and local taxes, including excise, penalty, franchise, payroll, mortgage recording, and transfer taxes, both directly and indirectly through its subsidiaries.

Risk of Investing in the United States. A decrease in imports or exports, changes in trade regulations 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.

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Proposed and adopted policy and legislative changes in the U.S. are changing many aspects of financial and other regulation and may have a significant effect on the U.S. markets generally, as well as on the value of certain securities. In addition, a continued rise in the U.S. public debt level or U.S. austerity measures may adversely affect U.S. economic growth and the securities to which the Fund has exposure.

The U.S. has developed increasingly strained relations with a number of foreign countries, including traditional allies, such as major European countries, the United Kingdom, Canada and Mexico, and historical adversaries, such as North Korea, Iran, China and Russia. If these relations were to worsen, 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 this trend were to continue, it may have an adverse impact on the U.S. economy and the issuers in which the Fund invests.

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., 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.

Tracking Error Risk. The Fund may be subject to tracking error, which is the divergence of the Fund’s performance from that of the Underlying Index. Tracking error may occur because of differences between the securities and other instruments held in the Fund’s portfolio and those included in the Underlying Index, pricing differences, differences in transaction costs, the Fund’s holding of uninvested cash, differences in timing of the accrual of or the valuation of dividends or interest, tax gains or losses, changes to the Underlying Index or the costs to the Fund of complying with various new or existing regulatory requirements. This risk may be heightened during times of increased market volatility or other unusual market conditions. Tracking error also may result because the Fund incurs fees and expenses, while the Underlying Index does not.

A Further Discussion of Other Risks

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

Close-out Risk for Qualified Financial Contracts. Recently adopted regulations of the prudential regulators, which are scheduled to take effect with respect to the Fund in 2019, will require counterparties that are part of U.S. or foreign global systemically important banking organizations to include contractual restrictions on close-out and cross-default in agreements relating to qualified financial contracts. Qualified financial contracts include agreements relating to swaps, currency forwards and other derivatives as well as repurchase agreements and securities lending agreements. The restrictions prevent the Fund from closing out a qualified financial contract during a

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specified time period if the counterparty is subject to resolution proceedings and prohibit the Fund from exercising default rights due to a receivership or similar proceeding of an affiliate of the counterparty. Implementation of these requirements may increase credit and other risks to the Fund.

Dividend Risk. There is no guarantee that issuers of the stocks held by the Fund will declare dividends in the future or that, if declared, such dividends will remain at current levels or increase over time.

Threshold/Underinvestment Risk. If certain aggregate ownership thresholds are reached either through the actions of BFA and its affiliates or the Fund, or as a result of third-party transactions, the ability of BFA and its affiliates on behalf of clients (including the Fund) to purchase or dispose of investments, or exercise rights or undertake business transactions, may be restricted by regulation or otherwise impaired. The capacity of the Fund to make investments in certain securities may be affected by the relevant threshold limits, and such limitations may have adverse effects on the liquidity and performance of the Fund’s portfolio holdings compared to the performance of the Underlying Index. This may increase the risk of the Fund being underinvested to the Underlying Index and increase the risk of tracking error.

Portfolio Holdings Information

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 top holdings of the Fund can be found at www.iShares.com. Fund fact sheets provide information regarding the Fund's top holdings and may be requested by calling 1-800-iShares (1-800-474-2737).

Management

Investment Adviser. 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 objective, 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).

Effective June 26, 2018, for its investment advisory services to the Fund, BFA is paid a management fee from the Fund calculated based on the aggregate average daily net assets of the following iShares funds: iShares Cohen & Steers REIT ETF, iShares iBoxx

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$ Investment Grade Corporate Bond ETF, iShares Intermediate-Term Corporate Bond ETF, iShares Long-Term Corporate Bond ETF, iShares MBS ETF, iShares Nasdaq Biotechnology ETF, iShares Russell 1000 Growth ETF, iShares Russell 1000 Value ETF, iShares Russell Mid-Cap ETF, iShares Russell Mid-Cap Growth ETF, iShares Russell Mid-Cap Value ETF, iShares S&P Mid-Cap 400 Growth ETF, iShares Short-Term Corporate Bond ETF and iShares TIPS Bond ETF.

The management fee for the Fund equals the ratio of the Fund’s net assets over the aggregate net assets of the above iShares funds multiplied by the amount calculated as follows: 0.3500% per annum of the aggregate net assets less than or equal to $121 billion, plus 0.3325% per annum of the aggregate net assets over $121 billion, up to and including $181 billion, plus 0.3159% per annum of the aggregate net assets over $181 billion, up to and including $231 billion, plus 0.3001% per annum of the aggregate net assets over $231 billion, up to and including $281 billion, plus 0.2851% per annum of the aggregate net assets in excess of $281 billion. Based on the assets of the iShares funds listed above, effective June 26, 2018, for its investment advisory services to the Fund, BFA is paid a management fee from the Fund, as a percentage of the Fund’s average daily net assets, at the annual rate of 0.34%.

Prior to June 26, 2018, for its investment advisory services to the Fund, BFA was paid a management fee from the Fund calculated based on the aggregate average daily net assets of the following iShares funds: iShares Cohen & Steers REIT ETF, iShares iBoxx $ Investment Grade Corporate Bond ETF, iShares Intermediate-Term Corporate Bond ETF, iShares MBS ETF, iShares Nasdaq Biotechnology ETF, iShares Russell 1000 Growth ETF, iShares Russell 1000 Value ETF, iShares Russell Mid-Cap ETF, iShares Russell Mid-Cap Growth ETF, iShares Russell Mid-Cap Value ETF, iShares S&P Mid-Cap 400 Growth ETF, iShares Short-Term Corporate Bond ETF and iShares TIPS Bond ETF. The management fee for the Fund equals the ratio of the Fund’s net assets over the aggregate net assets of the above iShares funds multiplied by the amount calculated as follows: 0.3500% per annum of the aggregate net assets less than or equal to $121 billion, plus 0.3325% per annum of the aggregate net assets over $121 billion, up to and including $181 billion, plus 0.3159% per annum of the aggregate net assets over $181 billion, up to and including $231 billion, plus 0.3001% per annum of the aggregate net assets over $231 billion, up to and including $281 billion, plus 0.2851% per annum of the aggregate net assets in excess of $281 billion. Based on the assets of the iShares funds listed above as of April 30, 2018, for its investment advisory services to the Fund, BFA was paid a management fee from the Fund, as a percentage of the Fund’s average daily net assets, at the annual rate of 0.34%. BFA may 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.

BFA is located at 400 Howard Street, San Francisco, CA 94105. It is an indirect wholly-owned subsidiary of BlackRock, Inc. (“BlackRock”). As of June 30, 2018, BFA and its affiliates provided investment advisory services for assets in excess of $6.29 trillion. BFA and its affiliates trade and invest for their own accounts in the actual securities and types of securities in which the Fund may also invest, which may affect the price of such securities.

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A discussion regarding the basis for the approval by the Trust's Board of Trustees (the “Board”) of the Investment Advisory Agreement with BFA is available in the Fund's semi-annual report for the period ended October 31.

Portfolio Managers. Rachel Aguirre, Diane Hsiung, Jennifer Hsui, Alan Mason, Greg Savage and Amy Whitelaw are primarily responsible for the day-to-day management of the Fund. Each Portfolio Manager is responsible for various functions related to portfolio management, including, but not limited to, investing cash inflows, coordinating with members of his or her portfolio management team to focus on certain asset classes, implementing investment strategy, researching and reviewing investment strategy and overseeing members of his or her portfolio management team that have more limited responsibilities.

Rachel Aguirre has been with BlackRock since 2006, including her years with Barclays Global Investors (“BGI’), which merged with BlackRock in 2009. Ms. Aguirre has been employed by BFA or its affiliates as a portfolio manager since 2006 and has been a Portfolio Manager of the Fund since 2018.

Diane Hsiung has been employed by BFA as a senior portfolio manager since 2007. Prior to that, Ms. Hsiung was a portfolio manager from 2002 to 2006 for Barclays Global Fund Advisors (“BGFA”). Ms. Hsiung has been a Portfolio Manager of the Fund since 2008.

Jennifer Hsui has been employed by BFA as a senior portfolio manager since 2007. Prior to that, Ms. Hsui was a portfolio manager from 2006 to 2007 for BGFA. Ms. Hsui has been a Portfolio Manager of the Fund since 2012.

Alan Mason has been employed by BFA as a portfolio manager since 1991. Mr. Mason has been a Portfolio Manager of the Fund since 2016.

Greg Savage has been employed by BFA as a senior portfolio manager since 2006. Prior to that, Mr. Savage was a portfolio manager from 2001 to 2006 for BGFA. Mr. Savage has been a Portfolio Manager of the Fund since 2008.

Amy Whitelaw has been with BlackRock since 1999, including her years with BGI, which merged with BlackRock in 2009. Ms. Whitelaw has been employed by BFA or its affiliates as a portfolio manager since 2009 and has been a Portfolio Manager of the Fund since 2018.

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 The PNC Financial Services Group, Inc., and their affiliates, directors, partners, trustees, managing members, officers and employees (collectively, the “Affiliates”)) 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 the other Affiliates provide investment

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management services to other funds and discretionary managed accounts that may follow investment programs similar to that of the Fund. BFA and the other 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 of the other Affiliates acts, or may act, as an investor, investment banker, research provider, investment manager, commodity pool operator, commodity trading advisor, financier, underwriter, adviser, market maker, trader, prime broker, lender, agent 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. Thus, it is likely that the Fund will have multiple business relationships with and will invest in, engage in transactions with, make voting decisions with respect to, or obtain services from, entities for which BFA or an Affiliate performs or seeks to perform investment banking or other services. Specifically, the Fund may invest in securities of, or engage in other transactions with, companies with which an Affiliate has developed or is trying to develop investment banking relationships or in which an Affiliate has significant debt or equity investments or other interests. 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, 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. The Fund may also make brokerage and other payments to Affiliates in connection with the Fund's portfolio investment transactions.

BFA or an Affiliate 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, including 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 Investment Company Act of 1940, as amended (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 having interests different from or adverse to, the securities that are owned by the Fund.

No 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 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’s or an Affiliate’s other clients have an adverse interest. Furthermore, transactions undertaken by Affiliate-advised clients may adversely impact the Fund. Transactions by

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one or more Affiliate-advised clients or by BFA 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 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 Fund has retained 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 retain a share of the securities lending revenues. BFA or an Affiliate will also receive compensation for managing the reinvestment of cash collateral. 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.

The activities of BFA or the Affiliates 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 Fund's SAI for further information.

Shareholder 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-iShares (1-800-474-2737) or visiting our website at www.iShares.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 “ICF.”

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 of the

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underlying securities held by the Fund, particularly for newly launched or smaller funds or in instances of significant volatility of the underlying securities.

The Board has adopted a policy of not monitoring for frequent purchases and redemptions of Fund shares (“frequent trading”) that appear to attempt to take advantage of a potential arbitrage opportunity presented by a lag between a change in the value of the Fund’s portfolio securities after the close of the primary markets for the Fund’s portfolio securities and the reflection of that change in the Fund’s NAV (“market timing”), because the Fund sells and redeems its shares directly through transactions that are in-kind and/or for cash, subject to the conditions described below under Creations and Redemptions . The Board has not adopted a policy of monitoring for other frequent trading activity because shares of the Fund are listed for trading on a national securities exchange.

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, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. The Fund’s primary listing exchange is Cboe BZX.

Section 12(d)(1) of the 1940 Act restricts investments by investment companies in the securities of other investment companies. Registered investment companies are permitted to invest in the Fund beyond the limits set forth in Section 12(d)(1), subject to certain terms and conditions set forth in SEC rules or in an SEC exemptive order issued to the Trust. In order for a registered investment company to invest in shares of the Fund beyond the limitations of Section 12(d)(1) pursuant to the exemptive relief obtained by the Trust, the registered investment company must enter into an agreement with the Trust.

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. Information regarding the intraday value of shares of the Fund, also known as the “indicative optimized portfolio value” (“IOPV”), is disseminated every 15 seconds throughout each trading day by the

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national securities exchange on which the Fund's shares are listed or by market data vendors or other information providers. The IOPV is based on the current market value of the securities or other assets and/or cash required to be deposited in exchange for a Creation Unit. The IOPV does not necessarily reflect the precise composition of the current portfolio of securities or other assets held by the Fund at a particular point in time or the best possible valuation of the current portfolio. Therefore, the IOPV should not be viewed as a “real-time” update of the Fund's NAV, which is computed only once a day. The IOPV is generally determined by using both current market quotations and price quotations obtained from broker-dealers and other market intermediaries that may trade in the portfolio securities or other assets held by the Fund. The quotations of certain Fund holdings may not be updated during U.S. trading hours if such holdings do not trade in the U.S. The Fund is not involved in, or responsible for, the calculation or dissemination of the IOPV and makes no representation or warranty as to its accuracy.

Determination of Net Asset Value. The NAV of the Fund normally is determined once daily Monday through Friday, generally as of the regularly scheduled close of business 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 are determined pursuant to valuation policies and procedures approved by the Board.

Equity investments and other instruments for which market quotations are readily available, as well as investments in an underlying fund, if any, are valued at market value, which is generally determined using the last reported official closing price or, if a reported closing price is not available, the last traded price on the exchange or market on which the security is primarily traded at the time of valuation.

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 business 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, the Fund’s investments are valued at fair value. Fair value determinations are made by BFA in accordance with policies and procedures approved by the Board. 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 liquidity 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

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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 closing market price of one or more assets or liabilities held by 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. Use of fair value prices and certain current market valuations could result in a difference between the prices used to calculate the Fund’s NAV and the prices used by the Underlying Index, which, in turn, could result in a difference between the Fund’s performance and the performance of the Underlying Index.

Dividends and Distributions

General Policies. Dividends from net investment income, if any, generally are declared and paid at least once a year 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 (“RIC”) 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. 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

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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 (other than qualified dividend 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. Distributions by the Fund of net long-term capital gains, if any, in excess of net short-term capital losses (capital gain dividends) are taxable to you as long-term capital gains, with a 25% capital gain tax rate to the extent attributable to 25% rate gain distributions received by the Fund from REITs, regardless of how long you have held the Fund’s shares. Distributions by the Fund that qualify as qualified dividend income are taxable to you at long-term capital gain rates. Long-term capital gains and qualified dividend income are generally eligible for taxation at a maximum rate of 15% or 20% for non-corporate shareholders, depending on whether their income exceeds certain threshold amounts. In addition, a 3.8% U.S. federal Medicare contribution tax is imposed on “net investment income,” including, but not limited to, interest, dividends, and net gain, of U.S. individuals with income exceeding $200,000 (or $250,000 if married and filing jointly) and of estates and trusts.

Dividends will be qualified dividend income to you if they are attributable to qualified dividend income received by the Fund. Generally, qualified dividend income includes dividend income from taxable U.S. corporations and qualified non-U.S. corporations, provided that the Fund satisfies certain holding period requirements in respect of the stock of such corporations and has not hedged its position in the stock in certain ways. Substitute dividends received by the Fund with respect to dividends paid on securities lent out will not be qualified dividend income. For this purpose, a qualified non-U.S. corporation means any non-U.S. corporation that is eligible for benefits under a comprehensive income tax treaty with the U.S., which includes an exchange of information program, or if the stock with respect to which the dividend was paid is readily tradable on an established U.S. securities market. The term excludes a corporation that is a passive foreign investment company.

Dividends received by the Fund from a REIT or another RIC generally are qualified dividend income only to the extent such dividend distributions are made out of qualified dividend income received by such REIT or RIC. It is expected that dividends received by the Fund from a REIT and distributed to a shareholder generally will be taxable to the shareholder as ordinary income.

For a dividend to be treated as qualified dividend income, the dividend must be received with respect to a share of stock held without being hedged by the Fund, and with respect to a share of the Fund held without being hedged by you, for 61 days during the 121-day period beginning at the date which is 60 days before the date on which such share becomes ex-dividend with respect to such dividend or, in the case of certain preferred stock, 91 days during the 181-day period beginning 90 days before such date.

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.

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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 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.

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 long-term capital gains or upon the sale or other disposition of shares of the Fund.

Distributions to certain foreign shareholders by a Fund at least 50% of the assets of which are “U.S. real property interests” (as defined in the U.S. Internal Revenue Code and U.S. Treasury regulations) at any time during the five-year period ending on the date of the distributions, to the extent the distributions are attributable to gains from sales or exchanges of U.S. real property interests (including shares in certain “U.S. real property holding corporations” such as certain REITs, although exceptions may apply if any class of stock of such a corporation is regularly traded on an established securities market and the Fund has held no more than 5% of such class of stock at any time during the five-year period ending on the date of the distributions), generally must be treated by such foreign shareholders as income effectively connected to a trade or business within the U.S., which is generally subject to tax at the graduated rates applicable to U.S. shareholders, except for distributions to foreign shareholders that held no more than 5% of any class of stock of the Fund at any time during the previous one-year period ending on the date of the distributions. Such distributions may be subject to U.S. withholding tax and may require a foreign shareholder to file a U.S. federal income tax return. In addition, sales or redemptions of shares held by certain foreign shareholders in such a Fund generally will be subject to U.S. withholding tax and generally will require the foreign shareholder to file a U.S. federal income tax return, although exceptions may apply if more than 50% of the value of the Fund’s shares are held by U.S. shareholders or the foreign shareholder selling or redeeming the shares has held no more than 5% of any class of stock of the Fund at any time during the five-year period ending on the date of the sale or redemption.

Provided that more than 50% of the value of a Fund’s stock is held by U.S. shareholders, redemptions and other distributions made in the form of U.S. real property interests (including shares in certain “U.S. real property holding corporations”, although exceptions may apply if any class of stock of such a corporation is regularly traded on an established securities market and the Fund has held no more than 5% of such class of stock at any time during the five-year period ending on the date of the distribution) generally will cause the Fund to recognize a

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portion of any unrecognized gain in the U.S. real property interests equal to the product of (i) the excess of fair market value of such U.S. real property interests over the Fund’s adjusted bases in such interests and (ii) the greatest foreign ownership percentage of the Fund during the five-year period ending on the date of distribution. In addition, the same rules apply with respect to distributions to a non-U.S. shareholder from the Fund and redemptions of a non-U.S. shareholder’s interest in the Fund attributable to a REIT’s distribution to the Fund of gain from the sale or exchange of U.S. real property or an interest in a U.S. real property holding corporation. The rule with respect to distributions and redemptions attributable to a REIT’s distribution to the Fund will not expire.

Separately, a 30% withholding tax is currently imposed on U.S.-source dividends, interest and other income items and will be imposed on proceeds from the sale, redemption or other disposition of property producing U.S.-source dividends and interest paid after December 31, 2018, to (i) foreign financial institutions, including non-U.S. investment funds, unless they agree to collect and disclose to the U.S. Internal Revenue Service (“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 your Fund shares are loaned out pursuant to a securities lending arrangement, you may lose the ability to treat Fund dividends paid while the shares are held by the borrower as qualified dividend income.

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

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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 of 50,000 shares or multiples thereof. Each “creator” or authorized participant (an “Authorized Participant”) has entered into an agreement with the Fund's distributor, BlackRock Investments, LLC (the “Distributor”), an affiliate of BFA.

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 (including any portion of such securities for which cash may be substituted) and a specified amount of cash approximating the holdings of the Fund in exchange for a specified number of Creation Units. To the extent practicable, the composition of such portfolio generally corresponds pro rata to the holdings of the Fund. However, creation and redemption baskets may differ. The Fund may, in certain circumstances, offer Creation Units partially or solely for cash.

Similarly, shares can be redeemed only in Creation Units, generally for a designated portfolio of securities (including any portion of such securities for which cash may be substituted) held by the Fund and a specified amount of cash. Except when aggregated in Creation Units, shares are not redeemable by the Fund.

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.

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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.

Costs Associated with Creations and Redemptions. Authorized Participants are charged standard creation and redemption transaction fees to offset transfer and other transaction costs associated with the issuance and redemption of Creation Units. The standard creation and redemption transaction fees are set forth in the table below. The standard creation transaction fee is charged to the Authorized Participant on the day such Authorized Participant creates a Creation Unit, and is the same regardless of the number of Creation Units purchased by the Authorized Participant on the applicable business day. Similarly, the standard redemption transaction fee is charged to the Authorized Participant on the day such Authorized Participant redeems a Creation Unit, and is the same regardless of the number of Creation Units redeemed by the Authorized Participant on the applicable business day. Creations and redemptions for cash (when cash creations and redemptions (in whole or in part) are available or specified) are also subject to an additional charge (up to the maximum amounts shown in the table below). This charge is intended to compensate for brokerage, tax, foreign exchange, execution, price movement and other costs and expenses related to cash transactions (which may, in certain instances, be based on a good faith estimate of transaction costs). Investors who use the services of a broker or other financial intermediary to acquire or dispose of Fund shares may pay fees for such services.

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The following table shows, as of May 31, 2018, the approximate value of one Creation Unit, standard fees and maximum additional charges for creations and redemptions (as described above and in the Fund's SAI):

*	As a percentage of the net asset value per Creation Unit, inclusive, in the case of redemptions, of the standard redemption transaction fee.

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.

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Distribution

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 1 University Square Drive, Princeton, NJ 08540.

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 iShares funds 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 iShares funds complex. 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 iShares funds 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.

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