# EDGAR Filing Document

**Accession Number:** 0000893818
**File Stem:** 0001193125-26-210998
**Filing Date:** 2026-5
**Character Count:** 33042
**Document Hash:** 160ff7fb4d88a088bf89ecad3f00e574
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-210998.hdr.sgml**: 20260507

**ACCESSION NUMBER**: 0001193125-26-210998

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 5

**FILED AS OF DATE**: 20260507

**DATE AS OF CHANGE**: 20260507

**EFFECTIVENESS DATE**: 20260507

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** BlackRock Funds III
- **CENTRAL INDEX KEY:** 0000893818

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 033-54126
- **FILM NUMBER:** 26951769

**BUSINESS ADDRESS:**
- **STREET 1:** 400 HOWARD STREET
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94105
- **BUSINESS PHONE:** 8006439691

**MAIL ADDRESS:**
- **STREET 1:** 400 HOWARD STREET
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94105

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** BARCLAYS GLOBAL INVESTORS FUNDS
- **DATE OF NAME CHANGE:** 20060201

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** BARCLAYS GLOBAL INVESTORS FUNDS INC
- **DATE OF NAME CHANGE:** 19990804

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MASTERWORKS FUNDS INC
- **DATE OF NAME CHANGE:** 19960607

## Series and Classes Contracts Data

### iShares MSCI Total International Index Fund (Series ID: S000033188)

| Class ID   | Class Name           | Ticker Symbol   |
|:---|:---|:---|
| C000102140 | Investor A Shares    |  |
| C000102141 | Institutional Shares |  |

**APRIL 30, 2026**![](g693107img5b4c76761.gif)

---

| | |
|:---|:---|
| ![](g693107bar.jpg)<br>| **Summary Prospectus** |

---

**BlackRock Funds III \| Investor A and Institutional Shares**

**●**

**iShares MSCI Total International Index Fund**

Investor A: BDOAX • Institutional: BDOIX

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), reports to shareholders and other information about the Fund, including the Fund's statement of additional information, online at https://www.blackrock.com/prospectus. You can also get this information at no cost by calling (800) 441-7762 or by sending an e-mail request to **prospectus.request@blackrock.com**, or from your financial professional. The Fund's prospectus and statement of additional information, both dated April 30, 2026, as amended and supplemented from time to time, are incorporated by reference into (legally made a part of) this Summary Prospectus.

*This Summary Prospectus contains information you should know before investing, including information about risks. Please read it before you invest and keep it for future reference.*

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

**Not FDIC Insured ● May Lose Value ● No Bank Guarantee**

------

Summary Prospectus

------

**Key Facts About iShares MSCI Total International Index Fund**

***Investment Objective***

------

The investment objective of iShares MSCI Total International Index Fund ("Total International Index Fund" or the "Fund"), a series of BlackRock Funds III (the "Trust"), is to match the performance of the MSCI All Country World Index ex USA Index (the "MSCI ACWI ex USA Index" or the "Underlying Index") in U.S. dollars with net dividends as closely as possible before the deduction of Fund expenses.

***Fees and Expenses of the Fund***

------

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Total International Index Fund. **You may pay other fees, such as brokerage commissions and other fees to your financial professional or your selected securities dealer, broker, investment adviser, service provider or industry professional (including BlackRock Fund Advisors ("BFA") and its affiliates) (each, a "Financial Intermediary"), which are not reflected in the table and example below.** 

---

| | | | | |
|:---|:---|:---|:---|:---|
| &nbsp;&nbsp; **Annual Fund Operating Expenses** <br> **(expenses that you pay each year as a** <br> **percentage of the value of your investment)**<sup>1</sup> <br>|  | **Investor A** <br> **Shares**<br>|  | **Institutional** <br> **Shares**<br>|
| Management Fee<sup>1,2</sup> <br>|  | 0.03% |  | 0.03% |
| Distribution and/or Service (12b-1) Fees |  | 0.25% |  |  |
| Other Expenses |  | 0.12% |  | 0.11% |
| &nbsp;&nbsp;&nbsp;&nbsp; Administration Fees | 0.01% |  | 0.01% |  |
| &nbsp;&nbsp;&nbsp;&nbsp; Miscellaneous Other Expenses | 0.10% |  | 0.09% |  |
| &nbsp;&nbsp;&nbsp;&nbsp; Interest Expense | 0.01% |  | 0.01% |  |
| Total Annual Fund Operating Expenses |  | 0.40% |  | 0.14% |
| Fee Waivers and/or Expense Reimbursements<sup>2,3</sup> <br>|  | 0.00% |  | 0.00% |
| Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements<sup>2,3</sup> <br>|  | 0.40% |  | 0.14% |

---

The fees and expenses shown in the table above and the example that follows include both the expenses of the Fund and its share of the allocated expenses of Total International ex U.S. Index Master Portfolio (the "Master Portfolio"), a series of Master Investment Portfolio ("MIP"). The management fees are paid by the Master Portfolio.

As described in the "Management of the Funds" section of the Fund's prospectus beginning on page 45, BFA, the investment adviser for the Master Portfolio, has contractually agreed to waive the management fee with respect to any portion of the Master Portfolio's assets estimated to be attributable to investments in other equity and fixed-income mutual funds and exchange-traded funds managed by BFA or its affiliates that have a contractual management fee, through June 30, 2027. In addition, BFA has contractually agreed to waive its management fees by the amount of investment advisory fees the Master Portfolio pays to BFA indirectly through its investment in money market funds managed by BFA or its affiliates, through June 30, 2027. The contractual agreements may be terminated upon 90 days' notice by a majority of the non-interested trustees of MIP or by a vote of a majority of the outstanding voting securities of the Master Portfolio.

As described in the "Management of the Funds" section of the Fund's prospectus beginning on page 45, BFA and BlackRock Advisors, LLC ("BAL"), the administrator for the Fund, have contractually agreed to waive and/or reimburse fees and/or expenses in order to limit Total Annual Fund Operating Expenses After Fee Waivers and/or Expense Reimbursements of the Fund (excluding Dividend Expense, Interest Expense, Acquired Fund Fees and Expenses and certain other Fund expenses) to 0.41% (for Investor A Shares) and 0.16% (for Institutional Shares) of average daily net assets through June 30, 2027. This contractual agreement may be terminated upon 90 days' notice by a majority of the non-interested trustees of the Trust or of MIP, as applicable, or by a vote of a majority of the outstanding voting securities of the Fund or the Master Portfolio, as applicable.

**Example:**

This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem 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** |
| Investor A Shares | &nbsp;&nbsp;&nbsp;&nbsp; $41 | &nbsp;&nbsp;&nbsp;&nbsp; $128 | &nbsp;&nbsp;&nbsp;&nbsp; $224 | &nbsp;&nbsp;&nbsp;&nbsp; $505 |
| Institutional Shares | &nbsp;&nbsp;&nbsp;&nbsp; $14 | &nbsp;&nbsp;&nbsp;&nbsp; $45 | &nbsp;&nbsp;&nbsp;&nbsp; $79 | &nbsp;&nbsp;&nbsp;&nbsp; $179 |

---

**2**

------

**Portfolio Turnover:**

The Master Portfolio pays 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 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 Master Portfolio's portfolio turnover rate was 13% of the average value of its portfolio.

***Principal Investment Strategies of the Fund***

------

The Total International Index Fund employs a "passive" management approach, attempting to invest in a portfolio of assets whose performance is expected to match approximately the performance of the MSCI ACWI ex USA Index. The Fund will be substantially invested in equity securities in the MSCI ACWI ex USA Index, and will invest, under normal circumstances, at least 80% of its net assets in securities or other financial instruments that are components of or have economic characteristics similar to the securities included in the MSCI ACWI ex USA Index. Equity securities in which the Fund invests consist primarily of common stock, preferred stock and securities or other instruments whose price is linked to the value of common stock.

The Fund will invest in the common stocks represented in the MSCI ACWI ex USA Index in roughly the same proportions as their weightings in the MSCI ACWI ex USA Index. The MSCI ACWI ex USA Index is a free float-adjusted market capitalization index that captures large and mid cap representation across 22 of 23 developed markets countries (excluding the United States) and 24 emerging markets countries. With 1,977 constituents, the index covers approximately 85% of the global equity opportunity set outside the United States. The component stocks have a market capitalization between $172.53 million and $1.36 trillion as of March 31, 2026. The Fund may also engage in futures transactions. At times, the Fund may not invest in all of the common stocks in the MSCI ACWI ex USA Index, or in the same weightings as in the MSCI ACWI ex USA Index. At those times, the Fund chooses investments so that the market capitalizations, industry weightings and other fundamental characteristics of the stocks chosen are similar to the MSCI ACWI ex USA Index as a whole. The Fund may lend securities with a value up to 33 <sup>1</sup>∕3% of its total assets to financial institutions that provide cash or securities issued or guaranteed by the U.S. Government as collateral. 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 MSCI ACWI ex USA Index is concentrated.

The Fund is a "feeder" fund that invests all of its assets in the Master Portfolio, which has the same investment objective and strategies as the Fund. All investments are made at the Master Portfolio level. This structure is sometimes called a "master/feeder" structure. The Fund's investment results will correspond directly to the investment results of the Master Portfolio. For simplicity, this prospectus uses the name of the Fund or the term "Fund" (as applicable) to include the Master Portfolio.

***Principal Risks of Investing in the Fund***

------

Risk is inherent in all investing. The value of your investment in the Total International Index Fund, as well as the amount of return you receive on your investment, may fluctuate significantly from day to day and over time. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. The following is a summary description of the principal risks of investing in the Fund. The relative significance of each risk factor below may change over time and you should review each risk factor carefully.

<sup>◼</sup>

***Concentration Risk*** *—* The Fund reserves the right to concentrate its investments (i.e., invest 25% or more of its total assets in securities of issuers in a particular industry) to approximately the same extent that the Underlying Index concentrates in a particular industry. To the extent the Fund concentrates in a particular industry, it may be more susceptible to economic conditions and risks affecting that industry.

<sup>◼</sup>

***Emerging Markets Risk*** — Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. Investments in emerging markets may be considered speculative. Emerging markets are more likely to experience hyperinflation and currency devaluations, which adversely affect returns to U.S. investors. In addition, many emerging financial markets have far lower trading volumes and less liquidity than developed markets.

<sup>◼</sup>

***Equity Securities Risk*** — Stock markets are volatile. The price of equity securities fluctuates based on changes in a company's financial condition and overall market and economic conditions.

<sup>◼</sup>

***Foreign Securities Risk*** — Foreign investments often involve special risks not present in U.S. investments that can increase the chances that the Fund will lose money. These risks include:

**3**

------

<sup>◼</sup>

The Fund generally holds its foreign securities and cash in foreign banks and securities depositories, which may be recently organized or new to the foreign custody business and may be subject to only limited or no regulatory oversight.

<sup>◼</sup>

Changes in foreign currency exchange rates can affect the value of the Fund's portfolio.

<sup>◼</sup>

The economies of certain foreign markets may not compare favorably with the economy of the United States with respect to such issues as growth of gross national product, reinvestment of capital, resources and balance of payments position.

<sup>◼</sup>

The governments of certain countries, or the U.S. Government with respect to certain countries, may prohibit or impose substantial restrictions through capital controls and/or sanctions on foreign investments in the capital markets or certain industries in those countries, which may prohibit or restrict the ability to own or transfer currency, securities, derivatives or other assets.

<sup>◼</sup>

Many foreign governments do not supervise and regulate stock exchanges, brokers and the sale of securities to the same extent as does the United States and may not have laws to protect investors that are comparable to U.S. securities laws.

<sup>◼</sup>

Settlement and clearance procedures in certain foreign markets may result in delays in payment for or delivery of securities not typically associated with settlement and clearance of U.S. investments.

<sup>◼</sup>

The Fund's claims to recover foreign withholding taxes may not be successful, and if the likelihood of recovery of foreign withholding taxes materially decreases, due to, for example, a change in tax regulation or approach in the foreign country, accruals in the Fund's net asset value for such refunds may be written down partially or in full, which will adversely affect the Fund's net asset value.

<sup>◼</sup>

The European financial markets have recently experienced volatility and adverse trends due to concerns about economic downturns in, or rising government debt levels of, several European countries, as well as acts of war in the region. These events may spread to other countries in Europe and may affect the value and liquidity of certain of the Fund's investments.

<sup>◼</sup>

***Futures Risk*** *—* The Fund's use of futures may reduce the Fund's returns. In these transactions, the Fund is subject to liquidity risk and correlation risk (i.e., that fluctuations in a future's value may not correlate with the change in market value of the instruments held by the Fund).

<sup>◼</sup>

***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 BlackRock 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.

<sup>◼</sup>

***Large-Capitalization Companies Risk*** — Large-capitalization companies may be less able than smaller-capitalization companies to adapt to changing market conditions and competitive challenges. Large-capitalization companies may be more mature and subject to more limited growth potential compared with smaller-capitalization companies. The performance of large-capitalization companies could trail the overall performance of the broader securities markets. Fund performance depends on the performance of individual securities to which the Fund has exposure. Changes in the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline.

<sup>◼</sup>

***Market Risk and Selection Risk*** — Market risk is the risk that one or more markets in which the Fund invests will go down in value, including the possibility that the markets will go down sharply and unpredictably. 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, exchange, country, group of countries, region, market, industry, group of industries, sector or asset class. Local, regional or global events such as war, acts of terrorism, the spread of infectious illness or other public health issues like pandemics or epidemics, recessions, or other events could have a significant impact on the Fund and its investments. Selection risk is the risk that the securities selected by Fund management will underperform the markets, the relevant indices or the securities selected by other funds with similar investment objectives and investment strategies. This means you may lose money.

**4**

------

<sup>◼</sup>

***Mid Cap Securities Risk*** — The securities of mid cap companies generally trade in lower volumes and are generally subject to greater and less predictable price changes than the securities of larger capitalization companies.

<sup>◼</sup>

***Operational and Technology Risks*** — The Fund is directly and indirectly susceptible to operational and technology risks, including those related to human errors, processing errors, communication errors, systems failures, cybersecurity incidents, and the use of artificial intelligence and machine learning ("AI"), which may result in losses for the Fund and its shareholders or may impair the Fund's operations. While the Fund's service providers are required to have appropriate operational, information security and cybersecurity risk management policies and procedures, their methods of risk management may differ from those of the Fund. Operational and technology risks for the issuers in which the Fund invests could also result in material adverse consequences for such issuers and may cause the Fund's investments in such issuers to lose value.

<sup>◼</sup>

***Passive Investment Risk*** *—* Because BFA does not select individual companies in the index that the Fund tracks, the Fund may hold securities of companies that present risks that an investment adviser researching individual securities might seek to avoid.

<sup>◼</sup>

***Preferred Securities Risk*** — Preferred securities may pay fixed or adjustable rates of return. Preferred securities are subject to issuer-specific and market risks applicable generally to equity securities. In addition, a company's preferred securities generally pay dividends only after the company makes required payments to holders of its bonds and other debt. For this reason, the value of preferred securities will usually react more strongly than bonds and other debt to actual or perceived changes in the company's financial condition or prospects. Preferred securities of smaller companies may be more vulnerable to adverse developments than preferred securities of larger companies.

<sup>◼</sup>

***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.

<sup>◼</sup>

***Small Cap and Emerging Growth Securities Risk*** — Small cap or emerging growth companies may have limited product lines or markets. They may be less financially secure than larger, more established companies. They may depend on a more limited management group than larger capitalized companies.

<sup>◼</sup>

***Tracking Error Risk*** *—* The Fund is subject to the risk of "tracking error," which is the divergence of the Fund's performance from that of the Underlying Index. Tracking error may occur due to a number of factors, including differences between the securities and other assets held in the Fund's portfolio and those included in the Underlying Index; differences in the timing and methodologies used to value securities and other assets; transaction costs and other expenses incurred by the Fund that the Underlying Index does not incur; the Fund's holding of uninvested cash; differences in the timing of the accrual or the valuation of dividends or interest received by the Fund or distributions paid to Fund shareholders; tax gains or losses; differences between the amount and/or timing of withholding taxes on dividends reflected in the Underlying Index from the Fund's obligation, if any, for foreign withholding taxes; the requirements for the Fund to maintain pass-through tax treatment; portfolio transactions carried out to minimize the distribution of capital gains to shareholders; changes to the Underlying Index, such as during a rebalancing or reconstitution; and impacts to the Fund of complying with certain regulatory requirements or limits. A fund that tracks an index composed of a large number of securities or other assets may experience greater tracking error than a fund that tracks a more narrow index. Tracking error risk may be heightened during times of increased market volatility or other unusual market conditions.

***Performance Information***

------

The information shows you how the performance of Total International Index Fund has varied year by year and provides some indication of the risks of investing in the Fund. The table compares the Fund's performance to that of the MSCI ACWI ex USA Index (Net). To the extent that dividends and distributions have been paid by the Fund, the performance information for the Fund in the chart and table assumes reinvestment of the dividends and distributions. As with all such investments, past performance (before and after taxes) is not an indication of future results. The table includes all applicable fees. If BFA, BAL and their affiliates had not waived or reimbursed certain Fund expenses during these periods, the Fund's returns would have been lower. Updated information on the Fund's performance, including its current net asset value, can be obtained by visiting www.blackrock.com or can be obtained by phone at (800) 882-0052.

**5**

------

**Investor A Shares** <br>**ANNUAL TOTAL RETURNS** <br>**iShares MSCI Total International Index Fund** <br>**As of 12/31**

![](g693107c000102140_dgf.jpg)

During the ten-year period shown in the bar chart, the highest return for a quarter was 17.10% (quarter ended June 30, 2020) and the lowest return for a quarter was -23.67% (quarter ended March 31, 2020).

---

| | | | |
|:---|:---|:---|:---|
| &nbsp;&nbsp; **For the periods ended 12/31/25**<br> **Average Annual Total Returns**<br>| **1 Year** | **5 Years** | **10 Years** |
| iShares MSCI Total International Index Fund — Investor A Shares |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp; Return Before Taxes | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 32.21<br> %<br>| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 7.37<br> %<br>| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 8.03<br> %<br>|
| &nbsp;&nbsp;&nbsp;&nbsp; Return After Taxes on Distributions | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 31.36<br> %<br>| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 6.86<br> %<br>| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 7.51<br> %<br>|
| &nbsp;&nbsp;&nbsp;&nbsp; Return After Taxes on Distributions and Sale of Fund Shares | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 19.74<br> %<br>| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 5.82<br> %<br>| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 6.53<br> %<br>|
| iShares MSCI Total International Index Fund — Institutional Shares |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp; Return Before Taxes | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 32.58<br> %<br>| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 7.66<br> %<br>| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 8.31<br> %<br>|
| &nbsp;&nbsp; MSCI ACWI ex USA Index (Net)<sup>1</sup> <br>(Reflects no deduction for fees, expenses or taxes except for withholding <br> taxes on reinvested dividends)<br>| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 32.39<br> %<br>| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 7.91<br> %<br>| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 8.41<br> %<br>|

---

1 Returns for net indices generally assume the reinvestment of dividends after the deduction of the maximum withholding tax in each country applicable to non-residents of the country as determined by the index provider. Such indices use withholding tax rates that are often at a higher rate than the rates to which the Fund is subject in each country, including for countries where the Fund is not subject to withholding taxes. When this is the case, index performance will be lower than if the index used the Fund's applicable withholding tax rates, if any.

After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor's tax situation and may differ from those shown, and the after-tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Investor A Shares only, and the after-tax returns for Institutional Shares will vary.

***Investment Adviser***

------

The Master Portfolio's investment adviser is BlackRock Fund Advisors (previously defined as "BFA").

***Portfolio Managers***

------

---

| | | |
|:---|:---|:---|
| **Portfolio Manager** | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; **Portfolio Manager of the** <br> **Master Portfolio Since**<br>| **Title** |
| Jennifer Hsui, CFA | 2016 | Managing Director of BlackRock, Inc. |
| Matt Waldron, CFA | 2025 | Managing Director of BlackRock, Inc. |
| Peter Sietsema, CFA | 2025 | Managing Director of BlackRock, Inc. |
| Steven White | 2025 | Managing Director of BlackRock, Inc. |

---

**6**

------

***Purchase and Sale of Fund Shares***

------

You may purchase or redeem shares of the Fund each day the New York Stock Exchange is open. To purchase or sell shares, you should contact your Financial Intermediary, or, if you hold your shares through the Fund, you should contact the Fund by phone at (800) 441-7762, by mail (c/o BlackRock Funds III, P.O. Box 534429, Pittsburgh, Pennsylvania 15253-4429), or by the Internet at www.blackrock.com. The Fund's initial and subsequent investment minimums generally are as follows, although the Fund may reduce or waive the minimums in some cases:

---

| | | |
|:---|:---|:---|
|  | **Investor A Shares** | **Institutional Shares** |
| **Minimum Initial**<br> **Investment**<br>| &nbsp;&nbsp; $1,000 for all accounts except:<br> •$50, if establishing an Automatic Investment <br> Plan.<br>•There is no investment minimum for employer-<br> sponsored retirement plans (not including SEP <br> IRAs, SIMPLE IRAs or SARSEPs).<br>•There is no investment minimum for certain fee-<br> based programs.<br>| &nbsp;&nbsp; There is no minimum initial investment for: <br> •Employer-sponsored retirement plans (not <br> including SEP IRAs, SIMPLE IRAs or SARSEPs), <br> state sponsored 529 college savings plans, <br> collective trust funds, investment companies or <br> other pooled investment vehicles, unaffiliated <br> thrifts and unaffiliated banks and trust <br> companies, each of which may purchase shares <br> of the Fund through a Financial Intermediary that <br> has entered into an agreement with the Fund's <br> distributor to purchase such shares.<br>•Clients of Financial Intermediaries that: (i) charge <br> such clients a fee for advisory, investment <br> consulting, or similar services or (ii) have entered <br> into an agreement with the Fund's distributor to <br> offer Institutional Shares through a no-load <br> program or investment platform.<br>•Clients investing through a self-directed IRA <br> brokerage account program sponsored by a <br> retirement plan record-keeper, provided that such <br> program offers only mutual fund options and that <br> the program maintains an account with the Fund <br> on an omnibus basis.<br>$2 million for individuals and "Institutional <br> Investors," which include, but are not limited to, <br> endowments, foundations, family offices, local, <br> city, and state governmental institutions, <br> corporations and insurance company separate <br> accounts who may purchase shares of the Fund <br> through a Financial Intermediary that has entered <br> into an agreement with the Fund's distributor to <br> purchase such shares. <br>$1,000 for:<br> •Clients investing through Financial Intermediaries <br> that offer such shares on a platform that charges <br> a transaction based sales commission outside of <br> the Fund.<br>•Tax-qualified accounts for insurance agents that <br> are registered representatives of an insurance <br> company's broker-dealer that has entered into an <br> agreement with the Fund's distributor to offer <br> Institutional Shares, and the family members of <br> such persons.<br>|
| **Minimum Additional**<br> **Investment**<br>| &nbsp;&nbsp; $50 for all accounts (with the exception of certain <br> employer-sponsored retirement plans which may <br> have a lower minimum).<br>| No subsequent minimum. |

---

***Tax Information***

------

The Fund's dividends and distributions may be subject to U.S. federal income taxes and may be taxed as ordinary income or capital gains, unless you are a tax-exempt investor or are investing through a qualified tax-exempt plan described in section 401(a) of the Internal Revenue Code of 1986, as amended, in which case you may be subject to U.S. federal income tax when distributions are received from such tax-deferred arrangements.

**7**

------

***Payments to Broker/Dealers and Other Financial Intermediaries***

------

If you purchase shares of the Fund through a Financial Intermediary, the Fund and BlackRock Investments, LLC, the Fund's distributor, or its affiliates may pay the Financial Intermediary for the sale of Fund shares and related services.

These payments may create a conflict of interest by influencing the Financial Intermediary and your individual financial professional to recommend the Fund over another investment.

Ask your individual financial professional or visit your Financial Intermediary's website for more information.

**8**

------

[This page intentionally left blank]

------

[This page intentionally left blank]

------

[This page intentionally left blank]

------

INVESTMENT COMPANY ACT FILE # 811-07332

SPRO-TI-0426

![](g693107img5b4c76761.gif)

![](g693107gopaper.gif)

------