| iShares MBS ETF | ||||||||||||||||||||||||||||||||
| iSHARES® MBS ETF Ticker: MBB Stock Exchange: NYSE Arca | ||||||||||||||||||||||||||||||||
| 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 own shares of the Fund. The investment advisory agreement between iShares Trust (the “Trust”) and BlackRock Fund Advisors (“BFA”) (formerly, Barclays Global Fund Advisors (“BGFA”)) (the “Investment Advisory Agreement”) provides that BFA will pay all operating expenses of the Fund, except interest expenses, taxes, brokerage expenses, future distribution fees or expenses, and extraordinary expenses. “Acquired Fund Fees and Expenses” reflect the Fund's pro rata share of the fees and expenses incurred by 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 used to calculate the Fund's net asset value per share (“NAV”) and 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”). You may also incur usual and customary brokerage commissions 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) | ||||||||||||||||||||||||||||||||
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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: | ||||||||||||||||||||||||||||||||
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| 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 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 936% of the average value of its portfolio. | ||||||||||||||||||||||||||||||||
| Principal Investment Strategies | ||||||||||||||||||||||||||||||||
| The Fund seeks to track the investment results of the Barclays U.S. MBS Index (the “Underlying Index”), which measures the performance of investment-grade mortgage-backed pass-through securities issued by the Federal National Mortgage Association (“Fannie Mae”), Federal Home Loan Mortgage Corporation (“Freddie Mac”) and Government National Mortgage Association (“Ginnie Mae”). The Underlying Index includes fixed-rate mortgage-backed pass-through securities issued by Ginnie Mae, Fannie Mae and Freddie Mac that have 30-, 20-, 15-year maturities, as well as hybrid adjustable rate mortgages (“ARMs”). All securities in the Underlying Index must have a remaining weighted average maturity of at least one year; hybrid ARMs must be at least one year away from initial reset, must be investment-grade, and must have $250 million or more of outstanding face value. 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. BFA uses a “passive” or 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. 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 the Underlying Index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market capitalization and industry weightings), fundamental characteristics (such as return variability, duration, maturity, credit ratings and yield) and liquidity measures similar to those of the Underlying Index. The Fund may or may not hold all of the securities in the Underlying Index. The Fund seeks to track the performance of the Underlying Index by investing at least 90% of its assets in the securities of the Underlying Index and in investments that provide substantially similar exposure to securities in the Underlying Index. The Fund may invest the remainder of its assets in certain futures, options and swap contracts, cash and cash equivalents, including shares of money market funds advised by BFA or its affiliates, as well as in securities not included in the Underlying Index, but which BFA believes will help the Fund track the Underlying Index. The Fund seeks to track the investment results of the Underlying Index before fees and expenses of the Fund. The Fund may lend securities representing up to one-third of the value of the Fund's total assets (including the value of the collateral received). As of December 31, 2014, approximately 100% of the bonds represented in the Underlying Index were U.S. agency mortgage-backed pass-through securities. The Underlying Index is represented by approximately 98.77% fixed-rate mortgages and 1.23% hybrid ARMs. Most transactions in mortgage-backed pass-through securities 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 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. The Underlying Index is sponsored by Barclays Capital Inc. or its affiliates (the “Index Provider” or “Barclays”), which is independent 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 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 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. Asset Class Risk. Securities in the Underlying Index or in the Fund's portfolio may underperform in comparison to the general financial markets, a particular securities market or other asset classes. Call Risk. During periods of falling interest rates, an issuer of a callable bond held by the Fund may “call” or repay the security before its stated maturity, and the Fund may have to reinvest the proceeds at lower interest rates, resulting in a decline in the Fund's income. 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. 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. Financials Sector Risk. Performance of companies in the financials sector may be adversely impacted by many factors, including, among others, government regulations, economic conditions, credit rating downgrades, changes in interest rates, and decreased liquidity in credit markets. The impact of more stringent capital requirements, recent or future regulation on any individual financial company, or recent or future regulation on the financials sector as a whole cannot be predicted. High Portfolio Turnover Risk. The Fund may engage in active and frequent trading of its portfolio securities. High portfolio turnover (higher than 100%) 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 when interest rates fall. This decline can occur because the Fund may subsequently invest in lower-yielding bonds when bonds in its portfolio mature, bonds in the Underlying Index are substituted or the Fund otherwise needs to purchase additional bonds. Index-Related Risk. There is no guarantee that the Fund will achieve a high degree of correlation to the Underlying Index and therefore achieve its investment objective. Market disruptions and regulatory restrictions could have an adverse effect on the Fund’s ability to adjust its exposure to the required levels in order to track the Underlying Index. Errors in index data, index computations or the construction of the Underlying Index in accordance with its methodology 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, which may have an adverse impact on the Fund and its shareholders. Interest Rate Risk. An increase in interest rates may cause the value of securities held by the Fund to decline. Issuer Risk. Fund performance depends on the performance of individual securities to which the Fund has exposure. The Fund invests in municipal bonds of issuers that are primarily state or local governments or agencies. Changes to the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline. Liquidity Risk. Liquidity risk exists when particular investments are difficult to purchase or sell. This can reduce the Fund's returns because the Fund may be unable to transact at advantageous times or prices. Management Risk. As the Fund may not fully replicate the Underlying Index, it is subject to the risk that BFA's investment strategy 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. Market Trading Risk. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruptions in the creation/redemption process. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND'S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV. Mortgage-Backed Securities Risk. The Fund invests in mortgage-backed securities, some of which may not be backed by the full faith and credit of the U.S. government. Mortgage-backed securities are subject to prepayment risk and extension risk. Because of these risks, mortgage-backed securities react differently than other bonds to changes in interest rates. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain mortgage-backed securities. Default or bankruptcy of a counterparty to a TBA transaction would expose the Fund to possible loss. Passive Investment Risk. The Fund is not actively managed and BFA does not attempt to take defensive positions under any market conditions, including declining markets. Prepayment Risk. During periods of falling interest rates, an issuer of mortgages and other fixed-income securities may be able to repay principal prior to the security’s maturity, causing the Fund to have to reinvest in securities with a lower yield or higher risk of default, resulting in a decline in the Fund’s income or return potential. Risk of Investing in the United States. The Fund has significant exposure to U.S. issuers. Certain changes in the U.S. economy, such as when the U.S. economy weakens or when its financial markets decline, may have an adverse effect on the securities to which the Fund has exposure. Securities Lending Risk. The Fund may engage in securities lending. Securities lending involves the risk that the Fund may lose money because the borrower of the loaned securities fails to return the securities in a timely manner or at all. The Fund could also lose money in the event of a decline in the value of the 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. Tracking Error Risk. Tracking error is the divergence of the Fund’s performance from that of the Underlying Index. Tracking error may occur because of differences between the securities held in the Fund’s portfolio and those included in the Underlying Index, pricing differences, transaction costs, the Fund’s holding of uninvested cash, differences in timing of the accrual of distributions, changes to the Underlying Index or the need to meet 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. U.S. Agency Debt Risk. The Fund invests in unsecured bonds or debentures issued by government agencies. Bonds or debentures issued by government agencies, including Fannie Mae and Freddie Mac, are generally backed only by the general creditworthiness and reputation of the government agency issuing the bond or debenture and are not backed by the full faith and credit of the U.S. government. As a result, there is uncertainty as to the current status of many obligations of Fannie Mae, Freddie Mac and other agencies that are placed under conservatorship of the federal government. Government National Mortgage Association (“Ginnie Mae”) securities are generally backed by the full faith and credit of the U.S. government. | ||||||||||||||||||||||||||||||||
| Performance Information | ||||||||||||||||||||||||||||||||
| The bar chart and table that follow show how the Fund has performed on a calendar year basis and provide an indication of the risks of investing in the Fund. 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. Supplemental information about the Fund’s performance is shown under the heading Total Return Information in the Supplemental Information section of the Prospectus. | ||||||||||||||||||||||||||||||||
| Year by Year Returns (Years Ended December 31) | ||||||||||||||||||||||||||||||||
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| The best calendar quarter return during the periods shown above was 3.83% in the 4th quarter of 2008; the worst was -2.24% in the 2nd quarter of 2013. Updated performance information is available at www.iShares.com or by calling 1-800-iShares (1-800-474-2737) (toll free). | ||||||||||||||||||||||||||||||||
| Average Annual Total Returns (for the periods ended December 31, 2014) | ||||||||||||||||||||||||||||||||
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