497K 1 d782868d497k.htm FORM 497K Form 497K
June 28, 2024
 
 
2024 Summary Prospectus
• iShares MBS ETF | MBB | NASDAQ
Before you invest, you may want to review the Fund’s prospectus, which contains more information about the Fund and its risks. You can find the Fund’s prospectus (including amendments and supplements) and other information about the Fund, including the Fund’s statement of additional information and shareholder reports, online at https://www.blackrock.com/prospectus. You can also get this information at no cost by calling 1-800-iShares (1-800-474-2737) or by sending an e-mail request to iSharesETFs@blackrock.com, or from your financial professional. The Fund’s prospectus and statement of additional information, both dated June 28, 2024, as amended and supplemented from time to time, are incorporated by reference into (legally made a part of) this Summary Prospectus. Information on the Fund’s net asset value, market price, premiums and discounts, and bid-ask spreads can be found at https://www.iShares.com.

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


iSHARES® MBS ETF
Ticker: MBBStock Exchange: Nasdaq
Investment Objective
The iShares MBS ETF (the Fund) seeks to track the investment results of an index composed of investment-grade mortgage-backed pass-through securities issued and/or guaranteed by U.S. government agencies.
Fees and Expenses
The following table describes the fees and expenses that you will incur if you buy, hold and sell shares of the Fund. The investment advisory agreement between 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: (i) the management fees, (ii) interest expenses, (iii) taxes, (iv) expenses incurred with respect to the acquisition and disposition of portfolio securities and the execution of portfolio transactions, including brokerage commissions, (v) distribution fees or expenses, and (vi) litigation expenses and any extraordinary expenses. The Fund may incur Acquired Fund Fees and Expenses. Acquired Fund Fees and Expenses reflect the Fund's pro rata share of the fees and expenses incurred indirectly by the Fund as a result of investing in other investment companies. The impact of Acquired Fund Fees and Expenses is included in the total returns of the Fund. Acquired Fund Fees and Expenses are not included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund's prospectus (the Prospectus). BFA, the investment adviser to the Fund, has contractually agreed to waive a portion of its management fee such that the Fund’s total annual fund operating expenses after the fee waiver will not exceed 0.04% through February 28, 2027. The contractual waiver may be terminated prior to February 28, 2027 only upon written agreement of the Trust and BFA.
You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below.
Annual Fund Operating Expenses
(ongoing expenses that you pay each year as a
percentage of the value of your investments)1
Management
Fees
Distribution
and Service
(12b-1) Fees
Other
Expenses2
Acquired Fund
Fees and
Expenses
Total Annual
Fund
Operating
Expenses
Fee Waiver
and/or
Expense
Reimbursement
Total Annual
Fund
Operating
Expenses After
Fee Waiver
and/or
Expense
Reimbursement
0.04%
None
0.00%
0.01%
0.05%
(0.01)%
0.04%

1
Operating expenses paid by BFA under the Investment Advisory Agreement exclude Acquired Fund Fees and Expenses, if any.
2
The amount rounded to 0.00%.
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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
$4
$13
$25
$61
Portfolio Turnover. The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or turns over its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in the Annual Fund Operating Expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 219% of the average value of its portfolio.
Principal Investment Strategies
The Fund seeks to track the investment results of the Bloomberg U.S. MBS Index (the Underlying Index), which measures the performance of investment-grade (as determined by Bloomberg Index Services Limited (the Index Provider or Bloomberg)) mortgage-backed pass-through securities (MBS) issued and/or guaranteed by U.S. government agencies or sponsored entities. The Underlying Index includes fixed-rate MBS issued by the Government National Mortgage Association (GNMA or Ginnie Mae), Federal National Mortgage Association (Fannie Mae)
and Federal Home Loan Mortgage Corporation (Freddie Mac) that have 30-, 20-, or 15-year maturities. All securities in the Underlying Index must have a remaining weighted average maturity of at least one year. In addition, the securities in the Underlying Index must be denominated in U.S. dollars and must be non-convertible. The Underlying Index is market capitalization-weighted and the securities in the Underlying Index are updated on the last business day of each month.
As of February 29, 2024, approximately 100% of the bonds represented in the Underlying Index were U.S. agency MBS. Most transactions in MBS occur through standardized contracts for future delivery in which the exact mortgage pools to be delivered are not specified until a few days prior to settlement (to-be-announced (TBA) transactions). The Fund may enter into such contracts for fixed-rate pass-through securities on a regular basis. The Fund, pending settlement of such contracts, will invest its assets in liquid, short-term instruments, including shares of money market funds advised by BFA or its affiliates. The Fund will assume its pro rata share of the fees and expenses of any money market fund that it may invest in, in addition to
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the Fund's own fees and expenses. The Fund may also acquire interests in mortgage pools through means other than such standardized contracts for future delivery.
BFA uses an indexing approach to try to achieve the Fund’s investment objective. Unlike many investment companies, the Fund does not try to beat the index it tracks and does not seek temporary defensive positions when markets decline or appear overvalued.
Indexing may eliminate the chance that the Fund will substantially outperform the Underlying Index but also may reduce some of the risks of active management, such as poor security selection. Indexing seeks to achieve lower costs and better after-tax performance by aiming to keep portfolio turnover low in comparison to actively managed investment companies.
BFA uses a representative sampling indexing strategy to manage the Fund. Representative sampling is an indexing strategy that involves investing in a representative sample of securities that collectively has an investment profile similar to that of an applicable underlying index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market value and industry weightings), fundamental characteristics (such as return variability, duration (i.e., a security's price sensitivity to a change in interest rates), maturity or credit ratings and yield) and liquidity measures similar to those of an applicable underlying index. The Fund may or may not hold all of the securities in the Underlying Index.
The Fund will invest at least 80% of its assets in the component securities of
the Underlying Index and TBAs that have economic characteristics that are substantially identical to the economic characteristics of the component securities of the Underlying Index, and the Fund will invest at least 90% of its assets in fixed income securities of the types included in the Underlying Index that BFA believes will help the Fund track the Underlying Index. The Fund will invest no more than 10% of its assets in futures, options and swaps contracts that BFA believes will help the Fund track the Underlying Index as well as in fixed income securities other than the types included in the Underlying Index, but which BFA believes will help the Fund track the Underlying Index. Cash and cash equivalent investments associated with a TBA position will be treated as part of that position for purposes of calculating the percentage of investments in the component securities of the Underlying Index. Cash and cash equivalent investments associated with a derivative position will be treated as part of that position for the purposes of calculating the percentage of investments included in the Underlying Index. The Fund seeks to track the investment results of the Underlying Index before fees and expenses of the Fund.
The Underlying Index is sponsored by Bloomberg, which isindependent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the securities in the Underlying Index and publishes information regarding the market value of the Underlying Index.
Industry Concentration Policy. The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in a particular industry or group of industries to approximately the same
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extent that the Underlying Index is concentrated. For purposes of this limitation, securities of the U.S. government (including its agencies and instrumentalities), repurchase agreements collateralized by U.S. government securities, and securities of state or municipal governments and their political subdivisions are not considered to be issued by members of any industry.
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. Certain key risks are prioritized below (with others following in alphabetical order), but the relative significance of any risk is difficult to predict and may change over time. You should review each risk factor carefully.
U.S. Agency Mortgage-Backed Securities Risk. The Fund invests in MBS issued or guaranteed by the U.S. government or one of its agencies or sponsored entities, some of which may not be backed by the full faith and credit of the U.S. government. MBS represent interests in pools of mortgages and are subject to interest rate, prepayment, and extension risk. MBS react differently to changes in interest rates than other bonds, and the prices of MBS may reflect adverse economic and market conditions. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of
certain MBS. MBS are also subject to the risk of default on the underlying mortgage loans, particularly during periods of economic downturn. Default or bankruptcy of a counterparty to a TBA transaction would expose the Fund to possible losses.
Credit Risk. Debt issuers and other counterparties may be unable or unwilling to make timely interest and/or principal payments when due or otherwise honor their obligations. Changes in an issuer’s credit rating or the market’s perception of an issuer’s creditworthiness may also adversely affect the value of the Fund’s investment in that issuer. The degree of credit risk depends on an issuer's or counterparty's financial condition and on the terms of an obligation.
Interest Rate Risk. Interest rate risk refers to fluctuations in the value of a fixed-income security due to changes in the general level of interest rates. An increase in interest rates generally will cause the value of fixed-income securities to decline. Securities with longer maturities generally are more sensitive to interest rate changes and subject to greater fluctuations in value. Changes in interest rates may have unpredictable effects on fixed-income markets and result in heightened market volatility and lower liquidity for certain instruments, all of which may adversely affect the Fund’s performance. Interest rate changes can be sudden and unpredictable and are influenced by a number of factors, including government policy, monetary policy, inflation expectations, perceptions of risk, and supply and demand for fixed-income securities.
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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, pandemics or other public health issues, recessions, the prospect or occurrence of a sovereign default or other financial crisis, or other events could have a significant impact on the Fund and its investments and could result in increased premiums or discounts to the Fund’s NAV.
Index-Related Risk. The Index Provider may rely on various sources of information to assess the criteria of components of the Underlying Index, including information that may be based on assumptions and estimates. Neither the Fund nor BFA can offer assurances that the Index Provider’s methodology or sources of information will provide an accurate assessment of included components. Errors in index data, index computations or the construction of the Underlying Index in accordance with its methodology may occur, and the Index Provider may not identify or correct them promptly or at all, which may have an adverse impact on the Fund and its shareholders. Unusual market conditions or other unforeseen circumstances (such as natural disasters, political unrest or war) may impact the Index Provider or a third-party data provider and could cause the Index Provider to postpone a scheduled rebalance. This could cause the Underlying Index to vary from its normal or expected composition.
Asset Class Risk. The securities and other assets in the Underlying Index or in the Fund’s portfolio may underperform in comparison to financial markets generally, a particular financial
market, another index, or other asset classes.
Authorized Participant Concentration Risk. An Authorized Participant is a member or participant of a clearing agency registered with the SEC, which has a written agreement with the Fund or one of its service providers that allows the Authorized Participant to place orders for the purchase and redemption of creation units (Creation Units). Only an Authorized Participant may engage in creation or redemption transactions directly with the Fund. There are a limited number of institutions that may act as Authorized Participants for the Fund, including on an agency basis on behalf of other market participants. No Authorized Participant is obligated to engage in creation or redemption transactions. To the extent that Authorized Participants exit the business or do not place creation or redemption orders for the Fund and no other Authorized Participant places orders, Fund shares are 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 or other assets of one or more issuers, countries or other geographic units, markets, industries, project types, or asset classes.
Cybersecurity Risk. Failures or breaches of the electronic systems of the Fund, its adviser, distributor,Index Provider, other service providers, counterparties, or issuers of assets in
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which the Fund invests may cause disruptions that negatively impact 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. The Fund cannot control the cybersecurity plans and systems of its service providers, counterparties, and other third parties whose activities affect the Fund.
Extension Risk. During periods of rising interest rates, certain debt obligations may be paid off substantially more slowly than originally anticipated and the value of those securities may fall sharply, resulting in a decline in the Fund’s income and potentially in the value of the Fund’s investments.
High Portfolio Turnover Risk. 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.
Income Risk. The Fund's income may decline if interest rates fall. This decline in income can occur because the Fund may subsequently invest in lower-yielding bonds as bonds in its portfolio mature, are near maturity or are called, bonds in the Underlying Index are substituted, or the Fund otherwise needs to purchase additional bonds.
Issuer Risk. The performance of the Fund depends on the performance of individual securities or other assets to which the Fund has exposure. The value of securities or other assets may decline, or perform differently from the
market as a whole, due to changes in the financial condition or credit rating of the issuer or counterparty.
Large Shareholder and Large-Scale Redemption Risk. Certain shareholders of the Fund, including an Authorized Participant, a third-party investor, the Fund’s adviser, an affiliate of the Fund’s adviser, a market maker, or another entity, may from time to time own or manage a substantial amount of Fund shares, or may hold their investment in the Fund for a limited period of time. There can be no assurance that any large shareholder or large group of shareholders would not redeem their investment. Redemptions of a large number of Fund shares could require the Fund to dispose of assets to meet the redemption requests, which can accelerate the realization of taxable income and/or capital gains and cause the Fund to make taxable distributions to its shareholders earlier than the Fund otherwise would have. In addition, under certain circumstances, non-redeeming shareholders may be treated as receiving a disproportionately large taxable distribution during or with respect to such year. In some circumstances, the Fund may hold a relatively large proportion of its assets in cash in anticipation of large redemptions, diluting its investment returns. These large redemptions may also force the Fund to sell portfolio securities or other assets when it might not otherwise do so, which may negatively impact the Fund’s NAV, increase the Fund’s brokerage costs and/or have a material effect on the market price of Fund shares.
Management Risk. The Fund is not actively managed, and BFA generally does not attempt to take defensive positions under any market conditions,
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including declining markets. As the Fund will not fully replicate the Underlying Index and may hold securities or other assets not included in the Underlying Index, it is subject to the risk that the investment strategy of BFA may not produce the intended results. There is no guarantee that the Fund’s investment results will have a high degree of correlation to those of the Underlying Index or that the Fund will achieve its investment objective.
Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares (including through a trading halt), losses from trading in secondary markets, periods of high volatility, and disruptions in the process of creating and redeeming Fund shares. Any of these factors, among others, may lead to the Fund’s shares trading in the secondary market at a premium or discount to NAV or to the intraday value of the Fund’s portfolio holdings. If you buy Fund shares at a time when the market price is at a premium to NAV or sell Fund shares at a time when the market price is at a discount to NAV, you may pay significantly more or receive significantly less than the underlying value of the Fund shares.
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.
Prepayment Risk. During periods of falling interest rates, issuers of certain debt obligations may repay principal prior to the security’s maturity, which may cause the Fund to have to reinvest in securities with lower yields or higher risk of default, resulting in a decline in the Fund’s income or return potential.
Risk of Investing in the U.S. Investing in U.S. issuers subjects the Fund to legal, regulatory, political, currency, security, and economic risks that are specific to the U.S. Certain changes in the U.S., such as a weakening of the U.S. economy or a decline in its financial markets, may have an adverse effect on U.S. issuers.
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, transaction costs incurred by the Fund, the Fund’s holding of uninvested cash, differences in timing of the accrual or the valuation of distributions, the requirements to maintain pass-through tax treatment, portfolio transactions carried out to minimize the distribution of capital gains to shareholders, acceptance of custom baskets, changes to the Underlying Index or the costs to the Fund of complying with various new or existing regulatory requirements, among other reasons. 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
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and expenses, while the Underlying Index does not.
Valuation Risk. The price that the Fund could receive upon the sale (or other disposition) of a security or other asset may differ from the Fund’s valuation of the security or other asset, particularly for securities or other assets that trade in low volume or volatile markets or that are valued using a fair value methodology. The price received by the Fund also may differ from the value used by the Underlying Index. In addition, the value of the securities or other assets in the Fund’s portfolio may change on days or during time periods
when investors are not able to purchase or sell Fund shares. Authorized Participants that create or redeem Fund shares on days when the Fund is holding fair-valued securities or other assets may receive fewer or more shares, or lower or higher redemption proceeds, than they would have received had the securities or other assets not been fair valued or been valued using a different methodology. The ability to value investments may be impacted by technological issues or errors by pricing services or other third-party service providers.
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Performance Information
The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide some indication of the risks of investing in the Fund by showing how the Fund’s average annual returns for 1, 5, and 10 years compare with the Underlying Index. Both assume that all dividends and distributions have been reinvested in the Fund. Past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. If BFA had not waived certain Fund fees during certain periods, the Fund's returns would have been lower.
Calendar Year-by-Year Returns1

1
The Fund’s year-to-date return as of March 31, 2024 was -1.06%.
The best calendar quarter return during the periods shown above was 7.33% in the 4th quarter of 2023; the worst was -5.33% in the 3rd quarter of 2022.
Updated performance information, including the Fund’s current NAV, may be obtained by visiting our website at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free).
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Average Annual Total Returns
(for the periods ended December 31, 2023)
 
One Year
Five Years
Ten Years
(Inception Date: 3/13/2007)
Return Before Taxes
4.99%
0.20%
1.28%
Return After Taxes on Distributions1
3.51%
-0.73%
0.30%
Return After Taxes on Distributions and Sale of Fund
Shares1
2.92%
-0.23%
0.56%
Bloomberg U.S. MBS Index (Index returns do not reflect
deductions for fees, expenses, or taxes)
5.05%
0.25%
1.38%

1
After-tax returns in the table above are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state or local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown, and after-tax returns shown are not relevant to tax-exempt investors or investors who hold shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts (IRAs). Fund returns after taxes on distributions and sales of Fund shares are calculated assuming that an investor has sufficient capital gains of the same character from other investments to offset any capital losses from the sale of Fund shares. As a result, Fund returns after taxes on distributions and sales of Fund shares may exceed Fund returns before taxes and/or returns after taxes on distributions.
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Management
Investment Adviser. BlackRock Fund Advisors.
Portfolio Managers. James Mauro and Karen Uyehara (the Portfolio Managers) are primarily responsible for the day-to-day management of the Fund. Each Portfolio Manager supervises a portfolio management team. Mr. Mauro and Ms. Uyehara have been Portfolio Managers of the Fund since 2011 and 2021, 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 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 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.
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For more information visit www.iShares.com or call 1-800-474-2737
Investment Company Act file No.: 811-09729
IS-SP-MBB-0624