Form 497

IMPORTANT NOTICE REGARDING CHANGE IN

INVESTMENT POLICY

iShares^®

iShares Trust

Supplement dated December 29, 2022 (the “Supplement”)

to the Summary Prospectus, Prospectus, and

the Statement of Additional Information (the “SAI”), each dated December 1, 2022, for the iShares MSCI USA Small‑Cap Multifactor ETF (SMLF) and the iShares MSCI Intl Small‑Cap Multifactor ETF (ISCF) (collectively, the “Funds” and each a “Fund”)

The information in this Supplement updates information in, and should be read in conjunction with, the Summary Prospectus, Prospectus and SAI for each Fund.

The Board of Trustees (the “Board”) has approved the following changes for the Fund, which are expected to be implemented on or around March 1, 2023:



Ticker¹	Current Fund Name	New Fund Name	Current Underlying Index	New Underlying Index

SMLF	iShares MSCI USA Small‑Cap Multifactor ETF	iShares U.S. Small‑Cap Equity Factor ETF	MSCI USA Small Cap Diversified Multiple-Factor Index	STOXX U.S. Small‑Cap Equity Factor Index

ISCF	iShares MSCI Intl Small‑Cap Multifactor ETF	iShares International Small‑Cap Equity Factor ETF	MSCI World ex USA Small Cap Diversified Multiple-Factor Index	STOXX International Small‑Cap Equity Factor Index

Change to the Funds’ “Principal Investment Strategies”

The first three paragraphs of the section of the Summary Prospectus and Prospectus for SMLF entitled “Principal Investment Strategies” are deleted in their entirety and replaced with the following:

The Fund seeks to track the investment results of the STOXX U.S. Small‑Cap Equity Factor Index (the “Underlying Index”), which is a

For the purposes of this Supplement, each Fund will be referred to hereafter by its ticker symbol.

rules-based equity index provided by STOXX Ltd. (the “Index Provider” or “STOXX”). The Underlying Index is composed of small-capitalization equity securities from the STOXX US Small Cap Index (the “Parent Index”) that are selected and weighted using an optimization process designed to maximize exposure to four target factors: momentum, quality, value, and low volatility. The Underlying Index seeks to control exposure to, among other things, industries, limit turnover and maintain a level of risk similar to that of the Parent Index. The Parent Index is a free float market capitalization-weighted index designed to measure the performance of small-capitalization companies in the U.S. Small capitalization companies, as calculated by the Index Provider, represent approximately the bottom 15% of the investable market capitalization in the U.S. securities market, as determined by STOXX.

The momentum score is calculated from the following signals: price momentum, earnings momentum and earnings announcement drift (i.e., the difference between a stock’s performance on and immediately following an earnings announcement date).

The quality score is calculated from the following signals: gross profitability, share dilution, accruals, changes in net operating assets, carbon emissions intensity and greenhouse gas (“GHG”) reduction targets. Carbon emissions intensity is based on the issuer’s Scope 1 and Scope 2 GHG emissions (i.e., direct emissions from sources that an issuer owns or controls and indirect emissions from the issuer’s purchase of energy) relative to peers in its Industry Classification Benchmark (“ICB”) Supersector, as reported by Institutional Shareholder Services (“ISS”). The GHG targets signal is based on the robustness of an issuer’s GHG reduction targets, including whether they are part of the Science Based Targets initiative (“SBTi”) framework; this is assessed by ISS based on its own ESG ratings data and SBTi data.

The value score is calculated from the following signals: current book value‑to‑price ratio, dividend yield (i.e., 12‑month trailing dividend divided by total market capitalization), earnings yield (i.e., 12‑month net income divided by total market capitalization), cash flow yield (i.e., 12‑month cash flow divided by total market capitalization) and time series normalized cash flow yield over the previous 36 months.

The low volatility score is based on prior 12‑month volatility, as calculated by the Index Provider.

other constraints, such as country and sector exposures relative to the Parent Index, among others. The Underlying Index is reviewed and rebalanced quarterly.

As of September 30, 2022, the Underlying Index consisted of approximately 918 constituents, and a significant portion of the Underlying Index was represented by securities of companies in the financials and industrials industries or sectors. The components of the Underlying Index are likely to change over time.

The first three paragraphs of the section of the Summary Prospectus and Prospectus for ISCF entitled “Principal Investment Strategies” are deleted in their entirety and replaced with the following:

The Fund seeks to track the investment results of the STOXX International Small‑Cap Equity Factor Index (the “Underlying Index”), which is a rules-based equity index provided by STOXX Ltd. (the “Index Provider” or “STOXX”). The Underlying Index is composed of small-capitalization equity securities from the STOXX International Developed Markets Small Cap Index (the “Parent Index”) that are selected and weighted using an optimization process designed to maximize exposure to four target factors: momentum, quality, value, and low volatility. The Underlying Index seeks to control exposure to, among other things, industries and countries, limit turnover and maintain a level of risk similar to that of the Parent Index. The Parent Index is a free float market capitalization-weighted index designed to measure the performance of small-capitalization companies from developed market countries excluding the U.S. Small-capitalization companies, as calculated by the Index Provider, represent approximately the bottom 15% of the investable market capitalization of each developed market country included in the Parent Index, as determined by STOXX.

robustness of an issuer’s GHG reduction targets, including whether they are part of the Science Based Targets initiative (“SBTi”) framework; this is assessed by ISS based on its own ESG ratings data and SBTi data.

The low volatility score is based on prior 12‑month volatility, as calculated by the Index Provider.

The maximum weight of a single security is 10%, and the sum of security weights that are individually greater than 4.5% must be less than 22.5% of the Underlying Index. The Index Provider also applies other constraints, such as country and sector exposures relative to the Parent Index, among others. The Underlying Index is reviewed and rebalanced quarterly.

As of September 30, 2022, the Underlying Index consisted of approximately 1,143 constituents from companies in the following countries or regions: Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Hong Kong, Ireland, Israel, Italy, Japan, the Netherlands, New Zealand, Norway, Portugal, Singapore, Spain, Sweden, Switzerland and the United Kingdom (the “U.K.”).

As of September 30, 2022, a significant portion of the Underlying Index was represented by securities of companies in the industrials industry or sector. The components of the Underlying Index are likely to change over time.

Changes to the Funds’ Principal Risks

Changes to the following disclosures from the section entitled “Summary of Principal Risks” of the Summary Prospectus and the Prospectus for each Fund:

The sections entitled “Healthcare Sector Risk” on page S‑5, “Low Size Securities Risk” and “Momentum Securities Risk” on page S‑6, “Quality Stocks Risk” and “Technology Sector Risk” on page S‑7, and “Value Securities Risk” on page S‑8 of the Summary Prospectus and the Prospectus for SMLF are deleted in their entirety.

The sections entitled “Low Size Securities Risk” and “Momentum Securities Risk” on page S‑6, “Quality Stocks Risk” on page S‑7, and “Value Securities Risk” on page S‑9 of the Summary Prospectus and the Prospectus for ISCF are deleted in their entirety.

The last sentence of the section entitled “Reliance on Trading Partners Risk” on page S‑7 of the Summary Prospectus and the Prospectus for ISCF is deleted and replaced with the following:

Through its holdings of securities of certain issuers, the Fund is specifically exposed to Asian Economic Risk and European Economic Risk.

The following disclosure is added to the section entitled “Summary of Principal Risks” in the Summary Prospectus and the Prospectus for SMLF:

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

The following disclosures are added to the section entitled “Summary of Principal Risks” in the Summary Prospectus and the Prospectus for each Fund:

ESG Risk. To the extent that the Underlying Index uses criteria related to the ESG characteristics of issuers, this may limit the types and number of investment opportunities available to the Fund and, as a result, the Fund may underperform other funds whose underlying index does not use ESG criteria. The Underlying Index’s use of ESG criteria may result in the Fund investing in, or allocating greater weight to, securities or market sectors that underperform the market as a whole or underperform other funds that use ESG criteria. In addition, the use of representative sampling may result in divergence of the Fund’s overall ESG characteristics or ESG risk from those of the Underlying Index. The Index Provider may evaluate security-level ESG data and, if applicable, ESG objectives or constraints that are relevant to the Underlying Index only at index reviews or rebalances. Securities included in the Underlying Index may cease to meet the relevant ESG criteria but may nevertheless remain in the Underlying Index and the Fund until the next review or rebalance by the Index Provider. As a result, certain securities in the Underlying Index, or the Underlying Index as a whole, may not meet the relevant ESG objectives or constraints at all times.

Style Factors Risk. Each of the four equity style factors (i.e., momentum, quality, value and low volatility) that determine the weight of each component security in the Underlying Index has characteristics that may cause the Fund to underperform the Parent Index or the market as a whole.

Momentum Factor Risk. Stocks that previously exhibited relatively high momentum characteristics may not experience positive momentum or may experience more volatility than the market as a whole.

Quality Factor Risk. Stocks included in the Underlying Index are deemed by the Index Provider to be quality stocks based on a number of attributes, but there is no guarantee that the past performance of these stocks will continue. Companies that issue these stocks may experience lower than expected returns or may experience negative growth, as well as increased leverage, resulting in lower than expected or negative returns to Fund shareholders. Many attributes of an issuer, as well as various market, regulatory and other external factors, can affect a stock’s quality and performance, and their impact on the stock or its price can be difficult to predict.

Value Factor Risk. Securities issued by companies that may be perceived as undervalued, particularly securities of a company that appear to trade at a significant discount to the company’s intrinsic value, may fail to appreciate for long periods of time and may never realize their full potential value. The Index Provider may be unsuccessful in applying a factor that emphasizes such securities. Value securities have generally performed better than non‑value securities during periods of economic recovery, although there is no assurance that they will continue to do so. There may be periods where value securities go out of favor, thus causing the Fund’s performance to suffer.

Low Volatility Factor Risk. Securities in the Fund’s portfolio may be subject to price volatility, and the prices may not be any less volatile than the market as a whole, and could be more volatile.

Changes to the following disclosures from the section entitled “A Further Discussion of Principal Risks” of the Prospectus for each Fund:

The section entitled “Healthcare Sector Risk” on pages 4‑5, “Low Size Securities Risk” on page 7, “Momentum Securities Risk” and “Quality Stocks Risk” on page 10, “Technology Sector Risk” on page 11, and “Value Securities Risk” on page 12 of the Prospectus for SMLF are deleted in their entirety.

The section entitled “Low Size Securities Risk” on pages 8‑9, “Momentum Securities Risk” on page 11, “Quality Stocks Risk” on page 13, and “U.S. Economic Risk” and “Value Securities Risk” on page 16 of the Prospectus for ISCF are deleted in their entirety.

The following disclosure is added to the section entitled “A Further Discussion of Principal Risks” in the Prospectus for SMLF:

Industrials Sector Risk. The value of securities issued by companies in the industrials sector may be adversely affected by supply and demand changes related to their specific products or services and industrials sector products in general. The products of manufacturing companies may face obsolescence due to rapid technological developments and frequent new product introduction. Global events, trade disputes and changes in government regulations, economic conditions and exchange rates may adversely affect the performance of companies in the industrials sector. Companies in the industrials sector may be adversely affected by liability for environmental damage and product liability claims. The industrials sector may also be adversely affected by changes or trends in commodity prices, which may be influenced by unpredictable factors. Companies in the industrials sector, particularly aerospace and defense companies, may also be adversely affected by government spending policies because companies in this sector tend to rely to a significant extent on government demand for their products and services.

The following disclosures are added to the section entitled “A Further Discussion of Principal Risks” in the Prospectus for each Fund:

The Index Provider evaluates securities for inclusion and/or weighting in the Underlying Index based on ESG criteria and data provided by the Index Provider or third parties. The Index Provider’s evaluation of securities’ ESG characteristics depends on these criteria and data, which may vary by index provider, and no assurance can be given that they will be complete, accurate or current. In addition, the Index Provider may evaluate security-level ESG data (including ratings) and, if applicable, ESG objectives or constraints that are relevant to the Underlying Index only at index reviews or rebalances. Securities

included in the Underlying Index may cease to meet the relevant ESG criteria but may nevertheless remain in the Underlying Index and the Fund until the next review or rebalance by the Index Provider. As a result, certain securities in the Underlying Index, or the Underlying Index as a whole, may not meet the relevant ESG objectives or constraints at all times. If the ESG assessment of a security in the Underlying Index or the Fund changes, neither the Fund nor BFA accepts any liability in relation to such change. BFA does not monitor securities in the Underlying Index with respect to ESG objectives or constraints applied by the Index Provider and is not responsible for changes to the ESG assessment of a security in the Underlying Index between rebalances. In addition, BFA does not assess the validity of the Index Provider’s evaluation of the ESG characteristics of securities or the criteria and data used in such evaluation.

The impacts of risks related to ESG investing are likely to change over time, and new ESG risks may be identified as further data and information regarding ESG factors and impacts become available. In addition, methodologies for ESG investing continue to develop, and the ESG methodology applied by the Index Provider may change over time.

Momentum Factor Risk. Stocks that previously exhibited relatively high momentum characteristics may not experience positive momentum in the future or may experience more volatility than the market as a whole. The Index Provider may be unsuccessful in creating an index that emphasizes an allocation to momentum securities. In addition, there may be periods when the momentum style of investing is out of favor and the investment performance of the Fund may suffer.

Quality Factor Risk. The Fund invests in stocks that are deemed by the Index Provider to be of high quality based on a number of attributes, but there is no guarantee that the past performance of these stocks or their issuers will continue. The Index Provider may be unsuccessful in creating an index that emphasizes an allocation to quality stocks. The measures of a stock’s quality as identified by the Index Provider can be adversely affected by market, regulatory, political, environmental and other developments. The price of a stock also may be affected by attributes other than those considered by the Index Provider. The degree to which these attributes may affect a stock’s performance can be difficult to predict.

Value Factor Risk. Value securities are those issued by companies that may be perceived as undervalued. Value securities, particularly securities of a company that appear to trade at a significant discount to the company’s intrinsic value, may fail to appreciate for long periods of time and may never realize their full potential value. The Index Provider may be unsuccessful in creating an index that emphasizes an allocation to undervalued securities. Value securities have generally performed better than non‑value securities during periods of economic recovery, although there is no assurance that they will continue to do so. There may be periods where value securities go out of favor, thus causing the Fund’s performance to suffer.

Low Volatility Factor Risk. The value of the securities in the Fund’s portfolio may fluctuate, sometimes rapidly and unpredictably, including due to factors affecting markets generally or particular industries. This volatility may affect the Fund’s NAV. Securities in the Fund’s portfolio may be subject to price volatility, and the prices may not be any less volatile than the market as a whole, and could be more volatile. Events or financial circumstances affecting individual securities or sectors may increase the volatility of the Fund.

Changes to the Funds’ Other Risks

Changes to the following disclosures from the section entitled “A Further Discussion of Other Risks” of the Prospectus for each Fund:

The section entitled “Industrials Sector Risk” on page 14 of the Prospectus for SMLF is deleted in its entirety.

The section entitled “Materials Sector Risk” on page 21 of the Prospectus for ISCF is deleted in its entirety.

The following disclosures are added to the section entitled “A Further Discussion of Other Risks” of the Prospectus for SMLF:

Healthcare Sector Risk. The profitability of companies in the healthcare sector may be adversely affected by the following factors, among others: extensive government regulations, restrictions on government reimbursement for medical expenses, rising costs of medical products and services, pricing pressure, an increased emphasis on outpatient services, changes in the demand for medical products and services, a limited number of products, industry innovation, changes in technologies and other market developments. Many healthcare companies are heavily dependent on patent protection. The expiration of a company’s patents may adversely affect that company’s profitability. Many healthcare companies are subject to extensive litigation based on product liability and similar claims. Healthcare

companies are subject to competitive forces that may make it difficult to raise prices and, in fact, may result in price discounting. The U.S. Inflation Reduction Act of 2022 allows for the negotiation of prescription drug prices on behalf of Medicare recipients, which may result in reduced prescription prices. This could reduce some healthcare companies’ overall profitability. Many new products in the healthcare sector may be subject to regulatory approvals. The process of obtaining such approvals may be long and costly, and such efforts ultimately may be unsuccessful. Companies in the healthcare sector may be thinly capitalized and may be susceptible to product obsolescence. In addition, a number of legislative proposals concerning healthcare have been considered by the U.S. Congress in recent years. It is unclear what proposals will ultimately be enacted, if any, and what effect they may have on companies in the healthcare sector.

Real Estate Investment Risk. Companies that invest in real estate (“Real Estate Companies”), such as real estate investment trusts (“REITs”), real estate holding and operating companies, and real estate management or development companies, 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. In addition, to the extent a Real Estate Company has its own 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.

Illiquidity 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.

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.

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 the length and expense of such proceedings, the validity of the terms of the applicable loan may not be recognized 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, mandated closures or other commercial restrictions, 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.

Technology Sector Risk. Technology companies, including information technology companies, face intense competition, both domestically and internationally, which may have an adverse effect on a company’s profit margins. Technology companies may have limited product lines,

markets, financial resources or personnel. The products of technology companies may face obsolescence due to rapid technological developments, frequent new product introduction, unpredictable changes in growth rates and competition for the services of qualified personnel. Companies in the technology sector are heavily dependent on patent and other intellectual property rights. A technology company’s loss or impairment of these rights may adversely affect the company’s profitability. Companies in the technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action. The technology sector may also be adversely affected by changes or trends in commodity prices, which may be influenced or characterized by unpredictable factors.

The following disclosures are added to the section entitled “A Further Discussion of Other Risks” of the Prospectus for ISCF:

Basic Materials Industry Risk. Issuers in the basic materials industry may be adversely affected by commodity price volatility, exchange rate fluctuations, import controls and increased competition. Production of industrial materials often exceeds demand as a result of over-building or economic downturns, leading to poor investment returns. Issuers in the basic materials industry are at risk for environmental damage and product liability claims and may be adversely affected by depletion of resources, delays in technical progress, labor relations and government regulations.

Consumer Staples Sector Risk. Companies in the consumer staples sector may be affected by the regulation of various product components and production methods, marketing campaigns and changes in the global economy, consumer spending and consumer demand. Tobacco companies, in particular, may be adversely affected by new laws, regulations and litigation. Companies in the consumer staples sector may also be adversely affected by changes or trends in commodity prices, which may be influenced by unpredictable factors. These companies may be subject to severe competition, which may have an adverse impact on their profitability.

Changes to the Funds’ “Index Provider”

The section of the Prospectus for each Fund entitled “Index Provider” is deleted in its entirety and replaced with the following:

STOXX Ltd.^® is a global provider of over 6,000 strictly rules-based and transparent indices. Best known for the leading European equity indices EURO STOXX 50^®, STOXX Europe 50^® and STOXX Europe 600^®, STOXX Ltd. maintains and calculates the STOXX Global Index^® family, which consists of total market, broad and blue-chip indices for the

Americas, Europe, Asia, and Pacific, the sub‑regions Latin America and BIC (Brazil, India and China), and global markets. The STOXX indices are licensed to over 400 companies globally as benchmarks for exchange-traded funds, futures, options, structured products and passively managed investment funds.

In addition, STOXX Ltd. is the marketing agent for the indices of Deutsche Böerse Group, including the DAX Index.

STOXX Ltd. is part of Deutsche Böerse Group^®.

The first two paragraphs of the section of the Prospectus for each Fund entitled “Disclaimers” are deleted and replaced with the following:

The Index Provider, Deutsche Börse Group and their licensors, research partners or data providers have no relationship to the Fund or BFA, other than the licensing of the Underlying Index and the related trademarks for use in connection with the Fund.

The Index Provider, Deutsche Börse Group and their licensors, research partners or data providers do not:

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sponsor, endorse, sell or promote the Fund.

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recommend that any person invest in the Fund or any other securities.

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have any responsibility or liability for or make any decisions about the timing, amount or pricing of the Fund.

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have any responsibility or liability for the administration, management or marketing of the Fund.

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consider the needs of the Fund or the owners of the Fund in determining, composing or calculating the Underlying Index or have any obligation to do so.

The Index Provider, Deutsche Börse Group and their licensors, research partners or data providers give no warranty, and exclude any liability (whether in negligence or otherwise), in connection with the Fund or its performance.

The Index Provider does not assume any contractual relationship with the purchasers of the Fund, BFA or any other third parties.

Specifically,

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the Index Provider, Deutsche Börse Group and their licensors, research partners or data providers do not give any warranty, express or implied, and exclude any liability about:

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The results to be obtained by the Fund, the owner(s) of the Fund or any other person in connection with the use of the Underlying Index and the data included in the Underlying Index;

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The accuracy, timeliness, and completeness of the Underlying Index and its data;

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The merchantability and the fitness for a particular purpose or use of the Underlying Index and its data;

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The performance of the Fund generally.

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the Index Provider, Deutsche Börse Group and their licensors, research partners or data providers give no warranty and exclude any liability, for any errors, omissions or interruptions in the Underlying Index or its data;

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Under no circumstances will the Index Provider, Deutsche Börse Group or their licensors, research partners or data providers be liable (whether in negligence or otherwise) for any lost profits or indirect, punitive, special or consequential damages or losses, arising as a result of such errors, omissions or interruptions in the Underlying Index or its data or generally in relation to the Fund, even in circumstances where the Index Provider, Deutsche Börse Group or their licensors, research partners or data providers are aware that such loss or damage may occur.

The licensing agreement between the Fund and the Index Provider is solely for their benefit and not for the benefit of the owners of the Fund or any other third parties.

Changes to the Funds’ “Construction and Maintenance of the Underlying Indexes”

The section of the SAI for SMLF entitled “MSCI USA Small Cap Diversified Multiple-Factor Index” on page 41 is deleted in its entirety.

The section of the SAI for ISCF entitled “MSCI World ex USA Small Cap Diversified Multiple-Factor Index” on page 44 is deleted in its entirety.

The following replaces the first paragraph of the section entitled “The STOXX Indexes” on page 47 of the SAI for each Fund:

STOXX Total Market Indexes

Each of the STOXX Total Market Indexes is a subset of the STOXX Global Total Market index (the “Global TMI”), which represents 95 percent of the free float market capitalization worldwide, with a variable number of components. The STOXX global equity universe includes all common stocks and equities with similar characteristics from financial markets that provide real-time and historical component

and currency pricing. The Global TMI is the fraction of the STOXX investable universe listed on eligible stock exchanges. The STOXX Country Total Market indexes form the basis for all regional STOXX Total Market indexes (each, a “Regional TMI”). Each STOXX Country Total Market index aims to represent a broad market and covers at least 95 percent of the free float market capitalization of the respective country’s investable universe. Each of the STOXX Total Market Indexes is derived from its respective Regional TMI(s).

STOXX World Equity Indexes

The STOXX World Equity Indexes includes a number of regional, country and sector equity indexes which are modular components of the STOXX World AC All Cap Index (AC stand for All Countries). The STOXX World AC All Cap Index aims to provide a broad universe that includes all investable stocks, ADR’s and GDR’s from all developed and emerging markets in the world. Large Cap, Mid Cap and Small Cap Indexes provide coverage of approximately the top 70 percent, 85 percent and 95 percent of each respective countries’ free float-adjusted market capitalization. The universe for all countries besides China, is the combination of the respective STOXX Country Total Market Index, the respective country’s constituents in the STOXX GCC Total Market Index (a Regional TMI that aims to represent the Gulf Cooperation Council countries market, which consists of Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates) and the respective country’s constituents of the STOXX World DR Index (a free-float market capitalization-weighted index of depositary receipts whose universe includes ADRs and GDRs that are traded on the New York Stock Exchange, NASDAQ, or the London Stock Exchange). For China the universe is the aggregate of the STOXX China Total Market Index, the STOXX China A Total Market Index, the STOXX China P‑Chip Total Market Index, and the China constituents in the STOXX Global DR Index.

The following is added to the section entitled “The STOXX Indexes” of the SAI for SMLF:

STOXX U.S. Small‑Cap Equity Factor Index

Number of Components: approximately 918

Index Description. The STOXX U.S. Small‑Cap Equity Factor Index (the “Underlying Index”) is a subset of the STOXX US Small Cap Index (the “Parent Index”), which is a free float market capitalization-weighted index designed to measure the performance of small-capitalization companies in the U.S. Small-capitalization companies, as calculated by

the Index Provider, represent approximately the bottom 15% of the investable market capitalization in the U.S. securities market, as defined by STOXX. Free float market capitalization is calculated by multiplying the total market capitalization of a security by a free float factor, as determined by the Index Provider, to reflect the market capitalization of the number of shares available in the market (rather than that of the total number of shares outstanding). The Underlying Index is composed of small-capitalization equity securities from the Parent Index that are selected and weighted using an optimization process designed to maximize exposure to four target factors: momentum, quality, value, and low volatility. The Underlying Index also seeks to mitigate exposure to unintended systematic exposures, limit turnover and maintain a level of risk similar to that of the Parent Index.

Index Methodology. The momentum score is calculated from the following signals: price momentum, earnings momentum and earnings announcement drift (i.e., the difference between a stock’s performance on and immediately following an earnings announcement date).

The low volatility score is based on prior 12‑month volatility, as calculated by the Index Provider.

The Index Provider derives a composite score based on a combination of the four factors at the following weights: momentum, 30%; quality, 35%; value, 30%; and low volatility, 5%. The composite score is an input to the optimization process through which the Index Provider selects securities from the Parent Index and assigns weights.

The optimization process seeks to maximize the overall exposure to the four factors while applying certain constraints, which include the following:

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A constituent’s minimum weight is the greater of 0% and its weight in the Parent Index minus 2%.

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A constituent’s maximum weight is the lesser of its weight in the Parent Index plus 2% and 20 times its Parent Index weight.

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The maximum weight for a single issuer is 10% of the Underlying Index.

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The sum of issuer weights that are individually greater than 4.5% must be less than 22.5% of the Underlying Index.

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The maximum exposure to each ICB Industry (Level 1) (as defined by the Index Provider) must be within 2% of the exposure in the Parent Index.

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The maximum one‑way turnover at each quarterly rebalance is 5%.

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The maximum ex ante tracking error relative to the Parent Index is 1%.

•

Constraints are also applied for the minimum and maximum exposures to the four factors relative to the Parent Index.

•

A constituent’s maximum weight is also subject to liquidity constraints.

The Underlying Index is reviewed and rebalanced each March, June, September and December.

The following is added to the section entitled “The STOXX Indexes” of the SAI for ISCF:

STOXX International Small‑Cap Equity Factor Index

Number of Components: approximately 1,143

Index Description. The STOXX International Small‑Cap Equity Factor Index (the “Underlying Index”) is a subset of the STOXX International Developed Markets Small Cap Index (the “Parent Index”), which is a free float market capitalization-weighted index designed to measure the performance of small-capitalization companies from developed market countries excluding the U.S. Small-capitalization companies, as calculated by the Index Provider, represent approximately the bottom 15% of the investable market capitalization of each developed market country included in the Parent Index, as defined by STOXX. Free float

market capitalization is calculated by multiplying the total market capitalization of a security by a free float factor, as determined by the Index Provider, to reflect the market capitalization of the number of shares available in the market (rather than that of the total number of shares outstanding). The Underlying Index is composed of small-capitalization equity securities from the Parent Index that are selected and weighted using an optimization process designed to maximize exposure to four target factors: momentum, quality, value, and low volatility. The Underlying Index also seeks to mitigate exposure to unintended systematic exposures, limit turnover and maintain a level of risk similar to that of the Parent Index.

The low volatility score is based on prior 12‑month volatility, as calculated by the Index Provider.

The optimization process seeks to maximize the overall exposure to the four factors while applying certain constraints, which include the following:

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A constituent’s minimum weight is the greater of 0% and its weight in the Parent Index minus 2%.

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A constituent’s maximum weight is the lesser of its weight in the Parent Index plus 2% and 20 times its Parent Index weight.

•

The maximum weight for a single issuer is 10% of the Underlying Index.

•

The sum of issuer weights that are individually greater than 4.5% must be less than 22.5% of the Underlying Index.

•

The maximum exposure to each ICB Industry (Level 1) (as defined by the Index Provider) must be within 2% of the exposure in the Parent Index.

•

The exposure to a particular country must be within 5% of the exposure in the Parent Index.

•

The maximum one‑way turnover at each quarterly rebalance is 5%.

•

The maximum ex ante tracking error relative to the Parent Index is 1%.

•

Constraints are also applied for the minimum and maximum exposures to the four factors relative to the Parent Index.

•

A constituent’s maximum weight is also subject to liquidity constraints.

The Underlying Index is reviewed and rebalanced each March, June, September and December.

If you have any questions, please call 1‑800‑iShares (1‑800‑474‑2737).

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

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