# EDGAR Filing Document

**Accession Number:** 0000355437
**File Stem:** 0000355437-26-000134
**Filing Date:** 2026-2
**Character Count:** 40714
**Document Hash:** b32e8d8cc71357cee12c28db8ff986d7
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000355437-26-000134.hdr.sgml**: 20260227

**ACCESSION NUMBER**: 0000355437-26-000134

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 5

**FILED AS OF DATE**: 20260227

**DATE AS OF CHANGE**: 20260227

**EFFECTIVENESS DATE**: 20260227

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** DFA INVESTMENT DIMENSIONS GROUP INC
- **CENTRAL INDEX KEY:** 0000355437

**ORGANIZATION NAME:**
- **EIN:** 363129984
- **STATE OF INCORPORATION:** MD
- **FISCAL YEAR END:** 1031

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 002-73948
- **FILM NUMBER:** 26698362

**BUSINESS ADDRESS:**
- **STREET 1:** 6300 BEE CAVE ROAD
- **STREET 2:** BUILDING ONE
- **CITY:** AUSTIN
- **STATE:** TX
- **ZIP:** 78746
- **BUSINESS PHONE:** (512) 306-7400

**MAIL ADDRESS:**
- **STREET 1:** 6300 BEE CAVE ROAD
- **STREET 2:** BUILDING ONE
- **CITY:** AUSTIN
- **STATE:** TX
- **ZIP:** 78746

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** DFA SMALL CO FUND INC
- **DATE OF NAME CHANGE:** 19830621

## Series and Classes Contracts Data

### U.S. CORE EQUITY 1 PORTFOLIO (Series ID: S000000979)

| Class ID   | Class Name                                         | Ticker Symbol   |
|:---|:---|:---|
| C000002730 | U.S. CORE EQUITY 1 PORTFOLIO - INSTITUTIONAL CLASS | DFEOX           |
| C000268965 | ETF Class                                          |  |

![](img_8cb27b646ced4f1.jpg)<br>

## U.S. Core Equity 1 Portfolio
**SHARE CLASS (TICKER)**: INSTITUTIONAL CLASS (DFEOX)<br>

#### Summary Prospectus
February 28, 2026

Before you invest, you may want to review the Portfolio's Prospectus, which contains more information about the Portfolio and its risks. You can find the Portfolio's Prospectus and other information about the Portfolio, including the Statement of Additional Information (SAI) and most recent reports to shareholders, when available, online at https://www.dimensional.com/us-en/document-center. You can also get this information at no cost by calling collect to (512) 306-7400 or by sending an e-mail request to document_requests@dimensional.com. The Portfolio's Prospectus and SAI, both dated February 28, 2026, as may be supplemented, are incorporated by reference into this Summary Prospectus.<br>

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Investment Objective

The investment objective of the U.S. Core Equity 1 Portfolio (the "Portfolio") is to achieve long-term capital appreciation.

Fees and Expenses of the Portfolio

**This table describes the fees and expenses you may pay if you buy, hold or sell shares of the Portfolio. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and Example below.**

---

| | |
|:---|:---|
| **Shareholder Fees (fees paid directly from your investment): None** |  |
| **Annual Fund Operating Expenses (expenses that you pay each <br>year as a percentage of the value of your investment)** |  |
| Management Fee | **0.12%** |
| Other Expenses | **0.03%** |
| Total Annual Fund Operating Expenses | **0.15%** |

---

#### EXAMPLE
This Example is meant to help you compare the cost of investing in the Portfolio with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Portfolio for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Portfolio's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs whether you redeem or hold your shares would be:

---

| | | | |
|:---|:---|:---|:---|
| **1 Year** | **3 Years** | **5 Years** | **10 Years** |
| $15  | $48  | $85  | $192  |

---

#### PORTFOLIO TURNOVER
A fund generally pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover 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 Portfolio's performance. During the most recent fiscal year, the Portfolio's portfolio turnover rate was 2% of the average value of its investment portfolio.

<br> 2 Dimensional Fund Advisors

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Principal Investment Strategies

To achieve the U.S. Core Equity 1 Portfolio's investment objective, Dimensional Fund Advisors LP (the "Advisor") implements an integrated investment approach that combines research, portfolio design, portfolio management, and trading functions. As further described below, the Portfolio's design emphasizes long-term drivers of expected returns identified by the Advisor's research, while balancing risk through broad diversification across companies and sectors. The Advisor's portfolio management and trading processes further balance those long-term drivers of expected returns with shorter-term drivers of expected returns and trading costs.

The U.S. Core Equity 1 Portfolio is designed to purchase a broad and diverse group of equity securities within a market capitalization weighted universe (e.g., the larger the company, the greater the proportion of the universe it represents) of U.S. companies (the "U.S. Universe"). The Portfolio invests in companies of all sizes, with moderately increased exposure to smaller capitalization, lower relative price, and higher profitability companies as compared to their representation in the U.S. Universe. The Portfolio's moderately increased exposure to smaller capitalization, lower relative price, and higher profitability companies may be achieved by decreasing the allocation of the Portfolio's assets to larger capitalization, higher relative price, or lower profitability companies relative to their weight in the U.S. Universe. An equity issuer is considered to have a high relative price (i.e., a growth stock) primarily because it has a high price in relation to its book value. An equity issuer is considered to have a low relative price (i.e., a value stock) primarily because it has a low price in relation to its book value. In assessing relative price, the Advisor may consider additional factors such as price to cash flow or price to earnings ratios. An equity issuer is considered to have high profitability because it has high earnings or profits from operations in relation to its book value or assets. The criteria the Advisor uses for assessing relative price and profitability are subject to change from time to time.

As a non-fundamental policy, under normal circumstances, U.S. Core Equity 1 Portfolio will invest at least 80% of its net assets in equity securities of U.S. companies. The Advisor generally defines a U.S. company as one that is listed and principally traded on a securities exchange in the United States that is deemed appropriate by the Advisor.

The Advisor may also increase or reduce the U.S. Core Equity 1 Portfolio's exposure to an eligible company, or exclude a company, based on shorter-term considerations, such as a company's price momentum, short-run reversals, and investment characteristics. In assessing a company's investment characteristics, the Advisor considers ratios such as recent changes in assets divided by total assets. The criteria the Advisor uses for assessing a company's investment characteristics are subject to change from time to time. In addition, the Advisor seeks to reduce trading costs using a flexible trading approach that looks for opportunities to participate in the available market liquidity, while managing turnover and explicit transaction costs.

<br> U.S. Core Equity 1 Portfolio 3

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The U.S. Core Equity 1 Portfolio also may purchase or sell futures contracts and options on futures contracts for U.S. equity securities and indices to increase or decrease equity market exposure based on actual or expected cash inflows to or outflows from the Portfolio.

The U.S. Core Equity 1 Portfolio may lend its portfolio securities to generate additional income.

Principal Risks

Because the value of your investment in the Portfolio will fluctuate, there is the risk that you will lose money. An investment in the Portfolio is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a description of principal risks of investing in the Portfolio.

***Equity Market Risk:*** Even a long-term investment approach cannot guarantee a profit. Economic, market, environmental, political, and issuer-specific conditions and events will cause the value of equity securities, and a fund that owns them, to rise or fall. Stock markets are volatile, with periods of rising prices and periods of falling prices.

***Small and Mid-Cap Company Risk:*** Securities of small and mid-cap companies are often less liquid than those of large companies and this could make it difficult to sell a small or mid-cap company security at a desired time or price. As a result, small and mid-cap company stocks may fluctuate relatively more in price. In general, small and mid-capitalization companies are also more vulnerable than larger companies to adverse business or economic developments and they may have more limited resources.

***Profitability Investment Risk:*** High relative profitability stocks may perform differently from the market as a whole and an investment strategy purchasing these securities may cause a fund to at times underperform equity funds that use other investment strategies.

***Value Investment Risk:*** Value stocks may perform differently from the market as a whole and an investment strategy purchasing these securities may cause a fund to at times underperform equity funds that use other investment strategies. Value stocks can react differently to political, economic, and industry developments than the market as a whole and other types of stocks. Value stocks also may underperform the market for long periods of time.

***Derivatives Risk:*** Derivatives are instruments, such as futures contracts, and options thereon, whose value is derived from that of other assets, rates or indices. The use of derivatives for non-hedging purposes may be considered to carry more risk than other types of investments. When a fund uses derivatives, the fund will be directly exposed to the risks of those derivatives. Derivative instruments are subject to a

<br> 4 Dimensional Fund Advisors

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number of risks including counterparty, liquidity, interest rate, market, credit and management risks, as well as difficulties with respect to valuation. Changes in the value of a derivative may not correlate perfectly with the underlying asset, rate or index, and a fund could lose more than the principal amount invested.

***Securities Lending Risk:*** Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, a fund may lose money and there may be a delay in recovering the loaned securities. A fund could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. Securities lending also may have certain adverse tax consequences.

***Operational Risk:*** Operational risks include human error, changes in personnel, system changes, faults in communication, and failures in systems, technology, or processes, and the use of artificial intelligence and machine learning ("AI"). Various operational events or circumstances are outside a fund's or its advisor's control, including instances at third parties. A fund and its advisor seek to reduce these operational risks through controls and procedures. However, measures that seek to reduce these operational risks through controls and procedures may not address every possible risk and may be inadequate to address these risks.

***Cyber Security Risk:*** A fund and its service providers' use of internet, technology and information systems may expose the fund to potential risks linked to cyber security breaches of those technological or information systems. Cyber security breaches, amongst other things, could allow an unauthorized party to gain access to proprietary information, customer data, or fund assets, or cause the fund and/or its service providers to suffer data corruption or lose operational functionality.

Performance

The bar chart and table immediately following illustrate the variability of the Portfolio's returns and are meant to provide some indication of the risks of investing in the Portfolio. The bar chart shows the changes in the Portfolio's performance from year to year. The table illustrates how annualized returns for certain periods, both before and after taxes, compare with those of a broad measure of market performance. The Portfolio's past performance (before and after taxes) is not an indication of future results. Updated performance information for the Portfolio can be obtained by visiting https://www.dimensional.com/us-en/funds.

The after-tax returns presented in the table for the Portfolio 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 an investor's tax situation and may differ from those shown in the table. In addition, the after-tax returns shown are not relevant to investors who hold shares of the Portfolio through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.

<br> U.S. Core Equity 1 Portfolio 5

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**U.S. Core Equity 1 Portfolio Institutional Class Shares —Total Returns**<br>

![PerformanceBarChartData(2016:14.8, 2017:20.89, 2018:-7.79, 2019:30.18, 2020:16.42, 2021:27.54, 2022:-15.01, 2023:22.96, 2024:21.35, 2025:16)](img_2c93a2f01d2b4f1.jpg)

---

| | |
|:---|:---|
| **<u>January 2016-December 2025</u>** | **<u>January 2016-December 2025</u>** |
| Highest Quarter | Lowest Quarter |
| 22.16% 2020, Q2 | -24.35% 2020, Q1 |

---

---

| | | | |
|:---|:---|:---|:---|
| **Annualized Returns (%) <br>Periods ended December 31, 2025** |  |  |  |
|  | **1 Year** | **5 Years** | **10 Years** |
| **U.S. Core Equity 1 Portfolio** |  |  |  |
| Return Before Taxes | **16.00%** | **13.41%** | **13.79%** |
| Return After Taxes on Distributions | **15.69%** | **12.79%** | **13.16%** |
| Return After Taxes on Distributions and Sale of Portfolio Shares | **9.66%** | **10.60%** | **11.38%** |
| **Russell 3000<sup>®</sup> Index** |  |  |  |
| (reflects no deduction for fees, expenses or taxes) | **17.15%** | **13.15%** | **14.29%** |

---

Investment Advisor/Portfolio Management

Dimensional Fund Advisors LP serves as the investment advisor for the Portfolio. The following individuals are responsible for leading the day-to-day management of the Portfolio:

• **Jed S. Fogdall**, Global Head of Portfolio Management, Chairman of the Investment Committee, Vice President, and Senior Portfolio Manager of the Advisor, has been a portfolio manager of the Portfolio since 2012.

<br> 6 Dimensional Fund Advisors

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• **John A. Hertzer**, Vice President and Senior Portfolio Manager of the Advisor, has been a portfolio manager of the Portfolio since 2022.

• **Allen Pu,** Deputy Head of Portfolio Management, North America, member of the Investment Committee, Vice President, and Senior Portfolio Manager of the Advisor, has been a portfolio manager of the Portfolio since 2024.

Purchase and Redemption of Fund Shares

Investors may purchase or redeem shares of the Portfolio on each day that the New York Stock Exchange is scheduled to be open for business by first contacting the Portfolio's transfer agent at (888) 576-1167. Shareholders that invest in the Portfolio through a financial intermediary should contact their financial intermediary regarding purchase and redemption procedures. The Portfolio generally is available for investment only by institutional clients, clients of registered investment advisors, clients of financial institutions and a limited number of certain other investors as approved from time to time by the Advisor. All investments are subject to approval of the Advisor.

Tax Information

The dividends and distributions you receive from the Portfolio are taxable and generally will be taxed as ordinary income, capital gains, or some combination of both, unless you are investing through a tax-advantaged arrangement, such as a 401(k) plan or an individual retirement account, in which case distributions may be taxed as ordinary income when withdrawn from the plan or account.

Payments to Financial Intermediaries

If you purchase the Portfolio through a broker-dealer or other financial intermediary (such as a bank), the Portfolio and its related companies may pay the intermediary for the sale of the Portfolio shares and/or related services. These payments may create a conflict of interest by influencing the financial intermediary to recommend the Portfolio over another investment. Ask your financial advisor or visit your financial intermediary's website for more information.

<br> U.S. Core Equity 1 Portfolio 7

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---

| | |
|:---|:---|
| **Dimensional Fund Advisors LP<br>6300 Bee Cave Road, Building One <br>Austin, TX 78746 <br>(512) 306-7400**  | ![](img_a2eddfcf7e334f1.jpg) |
| DFA-022826-DFEOX<br>00322082 | ![](img_a2eddfcf7e334f1.jpg) |

---

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![](img_8cb27b646ced4f1.jpg)<br>

## DFA INVESTMENT DIMENSIONS GROUP INC.

---

| | | | |
|:---|:---|:---|:---|
|  | **Class:** | **Ticker:** | **Exchange:** |
| **U.S. Core Equity 1 Portfolio** | ETF Class shares | DSEO | NYSE Arca, Inc. |

---

#### Summary Prospectus
February 28, 2026

Before you invest, you may want to review the Portfolio's ETF Class shares Prospectus, which contains more information about the Portfolio and its risks. You can find the Portfolio's ETF Class shares Prospectus and other information about the Portfolio, including the Statement of Additional Information (SAI) and most recent reports to shareholders, when available, online at https://www.dimensional.com/us-en/document-center. You can also get this information at no cost by calling collect to (512) 306-7400 or by sending an e-mail request to document_requests@dimensional.com. The Portfolio's ETF Class shares Prospectus and SAI, both dated February 28, 2026, as may be supplemented, are incorporated by reference into this Summary Prospectus. **The Portfolio's ETF Class shares are listed on a national securities exchange and, unlike mutual fund shares, are not individually redeemable. In addition to the ETF Class shares, the Portfolio also offers a conventional mutual fund share class in a separate summary prospectus.**<br>

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Investment Objective

The investment objective of the U.S. Core Equity 1 Portfolio (the "Portfolio") is to achieve long-term capital appreciation.

Fees and Expenses of the Portfolio

**This table describes the fees and expenses you may pay if you buy, hold or sell ETF Class shares of the Portfolio. You may also incur usual and customary brokerage commissions when buying or selling the ETF Class shares of the Portfolio, which are not reflected in the table or Example that follows.**

---

| | |
|:---|:---|
| **Shareholder Fees (fees paid directly from your investment): None** |  |
| **Annual Fund Operating Expenses (expenses that you pay each <br>year as a percentage of the value of your investment)** |  |
| Management Fee | **0.12%** |
| Other Expenses<sup>1</sup> | **0.05%** |
| Total Annual Fund Operating Expenses | **0.17%** |
| Fee Waiver and/or Expense Reimbursement<sup>2</sup> | **0.02%** |
| Total Annual Fund Operating Expenses After Fee Waiver and/or Expense Reimbursement | **0.15%** |

---

<sup>1</sup> The ETF Class shares of the Portfolio are new, so the "Other Expenses" shown for the class are based on anticipated fees and expenses for the first full fiscal year.

<sup>2</sup> Dimensional Fund Advisors LP (the "Advisor") has agreed to waive certain fees and in certain instances, assume certain expenses of the ETF Class shares of the Portfolio. The Fee Waiver and/or Expense Assumption Agreement for the Portfolio will remain in effect through February 28, 2027, and may only be terminated by the Fund's Board of Directors prior to that date. Under certain circumstances, the Advisor retains the right to seek reimbursement for any fees previously waived and/or expenses previously assumed up to thirty-six months after such fee waiver and/or expense assumption.

#### EXAMPLE
This Example is meant to help you compare the cost of investing in the Portfolio's ETF Class shares with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Portfolio's ETF Class shares for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Portfolio's operating expenses remain the same. The costs for the Portfolio's ETF Class shares reflect the net expenses of the Portfolio's ETF Class shares that result from the contractual expense waiver in the first year only. Although your actual costs may be higher or lower, based on these assumptions your costs whether you redeem or hold your shares would be:

<br> 2 Dimensional Fund Advisors

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---

| | | | |
|:---|:---|:---|:---|
| **1 Year** | **3 Years** | **5 Years** | **10 Years** |
| $15  | $53  | $94  | $215  |

---

#### PORTFOLIO TURNOVER
A fund generally pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover 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 Portfolio's performance. During the most recent fiscal year, the portfolio turnover rate was 2% of the average value of its investment portfolio.

Principal Investment Strategies

To achieve the U.S. Core Equity 1 Portfolio's investment objective, Dimensional Fund Advisors LP (the "Advisor") implements an integrated investment approach that combines research, portfolio design, portfolio management, and trading functions. As further described below, the Portfolio's design emphasizes long-term drivers of expected returns identified by the Advisor's research, while balancing risk through broad diversification across companies and sectors. The Advisor's portfolio management and trading processes further balance those long-term drivers of expected returns with shorter-term drivers of expected returns and trading costs.

The U.S. Core Equity 1 Portfolio is designed to purchase a broad and diverse group of equity securities within a market capitalization weighted universe (e.g., the larger the company, the greater the proportion of the universe it represents) of U.S. companies (the "U.S. Universe"). The Portfolio invests in companies of all sizes, with moderately increased exposure to smaller capitalization, lower relative price, and higher profitability companies as compared to their representation in the U.S. Universe. The Portfolio's moderately increased exposure to smaller capitalization, lower relative price, and higher profitability companies may be achieved by decreasing the allocation of the Portfolio's assets to larger capitalization, higher relative price, or lower profitability companies relative to their weight in the U.S. Universe. An equity issuer is considered to have a high relative price (i.e., a growth stock) primarily because it has a high price in relation to its book value. An equity issuer is considered to have a low relative price (i.e., a value stock) primarily because it has a low price in relation to its book value. In assessing relative price, the Advisor may consider additional factors such as price to cash flow or price to earnings ratios. An equity issuer is considered to have high profitability because it has high earnings or profits from operations in relation to its book value or assets. The criteria the Advisor uses for assessing relative price and profitability are subject to change from time to time.

<br> U.S. Core Equity 1 Portfolio 3

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As a non-fundamental policy, under normal circumstances, U.S. Core Equity 1 Portfolio will invest at least 80% of its net assets in equity securities of U.S. companies. The Advisor generally defines a U.S. company as one that is listed and principally traded on a securities exchange in the United States that is deemed appropriate by the Advisor.

The Advisor may also increase or reduce the U.S. Core Equity 1 Portfolio's exposure to an eligible company, or exclude a company, based on shorter-term considerations, such as a company's price momentum, short-run reversals, and investment characteristics. In assessing a company's investment characteristics, the Advisor considers ratios such as recent changes in assets divided by total assets. The criteria the Advisor uses for assessing a company's investment characteristics are subject to change from time to time. In addition, the Advisor seeks to reduce trading costs using a flexible trading approach that looks for opportunities to participate in the available market liquidity, while managing turnover and explicit transaction costs.

The U.S. Core Equity 1 Portfolio also may purchase or sell futures contracts and options on futures contracts for U.S. equity securities and indices to increase or decrease equity market exposure based on actual or expected cash inflows to or outflows from the Portfolio.

The U.S. Core Equity 1 Portfolio may lend its portfolio securities to generate additional income.

The U.S. Core Equity 1 Portfolio's ETF Class operates as an actively managed exchange-traded fund ("ETF") and does not seek to replicate the performance of a specific index and may have a higher degree of portfolio turnover than passively managed index ETFs.

Principal Risks

Because the value of your investment in the Portfolio will fluctuate, there is the risk that you will lose money. An investment in the Portfolio is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The following is a description of principal risks of investing in the Portfolio.

***Equity Market Risk:*** Even a long-term investment approach cannot guarantee a profit. Economic, market, environmental, political, and issuer-specific conditions and events will cause the value of equity securities, and a fund that owns them, to rise or fall. Stock markets are volatile, with periods of rising prices and periods of falling prices.

***Small and Mid-Cap Company Risk:*** Securities of small and mid-cap companies are often less liquid than those of large companies and this could make it difficult to sell a small or mid-cap company security at a desired time or price. As a result, small and mid-cap company stocks may fluctuate relatively more in price. In general, small and

<br> 4 Dimensional Fund Advisors

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mid-capitalization companies are also more vulnerable than larger companies to adverse business or economic developments and they may have more limited resources.

***Profitability Investment Risk:*** High relative profitability stocks may perform differently from the market as a whole and an investment strategy purchasing these securities may cause a fund to at times underperform equity funds that use other investment strategies.

***Value Investment Risk:*** Value stocks may perform differently from the market as a whole and an investment strategy purchasing these securities may cause a fund to at times underperform equity funds that use other investment strategies. Value stocks can react differently to political, economic, and industry developments than the market as a whole and other types of stocks. Value stocks also may underperform the market for long periods of time.

***Derivatives Risk:*** Derivatives are instruments, such as futures contracts, and options thereon, whose value is derived from that of other assets, rates or indices. The use of derivatives for non-hedging purposes may be considered to carry more risk than other types of investments. When a fund uses derivatives, the fund will be directly exposed to the risks of those derivatives. Derivative instruments are subject to a number of risks including counterparty, liquidity, interest rate, market, credit and management risks, as well as difficulties with respect to valuation. Changes in the value of a derivative may not correlate perfectly with the underlying asset, rate or index, and a fund could lose more than the principal amount invested.

***Securities Lending Risk:*** Securities lending involves the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, a fund may lose money and there may be a delay in recovering the loaned securities. A fund could also lose money if it does not recover the securities and/or the value of the collateral falls, including the value of investments made with cash collateral. Securities lending also may have certain adverse tax consequences.

***Operational Risk:*** Operational risks include human error, changes in personnel, system changes, faults in communication, and failures in systems, technology, or processes, and the use of artificial intelligence and machine learning ("AI"). Various operational events or circumstances are outside a fund's or its advisor's control, including instances at third parties. A fund and its advisor seek to reduce these operational risks through controls and procedures. However, measures that seek to reduce these operational risks through controls and procedures may not address every possible risk and may be inadequate to address these risks.

***Cyber Security Risk:*** A fund and its service providers' use of internet, technology and information systems may expose the fund to potential risks linked to cyber security breaches of those technological or information systems. Cyber security breaches, amongst other things, could allow an unauthorized party to gain access to proprietary

<br> U.S. Core Equity 1 Portfolio 5

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information, customer data, or fund assets, or cause the fund and/or its service providers to suffer data corruption or lose operational functionality.

The following is a description of additional principal risks of investing in the ETF Class shares of the Portfolio, due to the shares being listed and traded on a national securities exchange.

***Market Trading Risk:*** Active trading markets for the ETF Class shares may not be developed or maintained by market makers or authorized participants. Authorized participants are not obligated to make a market in the ETF Class shares or to submit purchase or redemption orders for creation units, which may widen bid-ask spreads. Trading in shares on an exchange may be halted in certain circumstances. There can be no assurance that the requirements of the listing exchange necessary to maintain the listing of the ETF Class shares will continue to be met. Additionally, in stressed market conditions, the market for the ETF Class shares may become less liquid in response to deteriorating liquidity in the markets for the fund's portfolio holdings, which may cause a significant variance in the market price of the ETF Class shares and their underlying value as well as an increase in the ETF Class shares' bid-ask spread.

***Premium/Discount Risk:*** The net asset value ("NAV") of the ETF Class shares and the value of your investment may fluctuate. Disruptions to creations and redemptions or the market price of a fund's holdings, the existence of extreme market volatility or potential lack of an active trading market for shares may widen bid-ask spreads and result in shares trading at a significant premium or discount to NAV. If a shareholder purchases shares at a time when the market price is at a premium to the NAV or sells shares at a time when the market price is at a discount to the NAV, the shareholder may sustain losses.

Performance

The bar chart and table immediately following illustrate the variability of the Portfolio's returns and are meant to provide some indication of the risks of investing in the Portfolio. The ETF Class shares of the Portfolio are a new class of shares for which performance information is not available, and therefore, for periods prior to the inception of the ETF Class shares, the bar chart and table show performance information for the Institutional Class shares of the Portfolio, a mutual fund class of shares of the Portfolio not offered in this Prospectus. Returns of the ETF Class shares of the Portfolio may vary from the returns of the Institutional Class shares due to differences in expenses. The bar chart shows the changes in performance of the Institutional Class shares of the Portfolio from year to year. The table illustrates how annualized returns of the Institutional Class shares of the Portfolio for certain periods, both before and after taxes, compare with those of a broad measure of market performance. The Portfolio's past performance (before and after taxes) is not an indication of future results. Updated performance information for the Portfolio can be obtained by visiting https://www.dimensional.com/us-en/funds.

<br> 6 Dimensional Fund Advisors

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The after-tax returns presented in the table for the Portfolio 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 an investor's tax situation and may differ from those shown in the table. In addition, the after-tax returns shown are not relevant to investors who hold shares of the Portfolio through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.

**U.S. Core Equity 1 Portfolio Institutional Class Shares<sup>1</sup> —Total Returns**<br>

![PerformanceBarChartData(2016:14.8, 2017:20.89, 2018:-7.79, 2019:30.18, 2020:16.42, 2021:27.54, 2022:-15.01, 2023:22.96, 2024:21.35, 2025:16)](img_e28b642d869a4f2.jpg)

---

| | |
|:---|:---|
| **<u>January 2016-December 2025</u>** | **<u>January 2016-December 2025</u>** |
| Highest Quarter | Lowest Quarter |
| 22.16% 2020, Q2 | -24.35% 2020, Q1 |

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<br> U.S. Core Equity 1 Portfolio 7

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| | | | | |
|:---|:---|:---|:---|:---|
| **Annualized Returns (%) <br>Periods ended December 31, 2025** | **Annualized Returns (%) <br>Periods ended December 31, 2025** |  |  |  |
|  |  | **1 Year** | **5 Years** | **10 Years** |
| **U.S. Core Equity 1 Portfolio - Institutional Class Shares** | **U.S. Core Equity 1 Portfolio - Institutional Class Shares** |  |  |  |
|  | Return Before Taxes | **16.00%** | **13.41%** | **13.79%** |
|  | Return After Taxes on Distributions | **15.69%** | **12.79%** | **13.16%** |
|  | Return After Taxes on Distributions and Sale of Portfolio Shares | **9.66%** | **10.60%** | **11.38%** |
| **Russell 3000<sup>®</sup> Index** | **Russell 3000<sup>®</sup> Index** |  |  |  |
| (reflects no deduction for fees, expenses or taxes) | (reflects no deduction for fees, expenses or taxes) | **17.15%** | **13.15%** | **14.29%** |
| <sup>1.</sup> | As of December 31, 2025, the ETF Class shares of the Portfolio had not yet incepted. Performance shown prior to the inception date of the ETF Class shares is from the Portfolio's Institutional Class shares, a mutual fund class of shares of the Portfolio not offered in this Prospectus. Returns for the ETF Class shares and Institutional Class shares may vary due to differences in their expenses. | As of December 31, 2025, the ETF Class shares of the Portfolio had not yet incepted. Performance shown prior to the inception date of the ETF Class shares is from the Portfolio's Institutional Class shares, a mutual fund class of shares of the Portfolio not offered in this Prospectus. Returns for the ETF Class shares and Institutional Class shares may vary due to differences in their expenses. | As of December 31, 2025, the ETF Class shares of the Portfolio had not yet incepted. Performance shown prior to the inception date of the ETF Class shares is from the Portfolio's Institutional Class shares, a mutual fund class of shares of the Portfolio not offered in this Prospectus. Returns for the ETF Class shares and Institutional Class shares may vary due to differences in their expenses. | As of December 31, 2025, the ETF Class shares of the Portfolio had not yet incepted. Performance shown prior to the inception date of the ETF Class shares is from the Portfolio's Institutional Class shares, a mutual fund class of shares of the Portfolio not offered in this Prospectus. Returns for the ETF Class shares and Institutional Class shares may vary due to differences in their expenses. |

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Investment Advisor/Portfolio Management

Dimensional Fund Advisors LP serves as the investment advisor for the Portfolio. The following individuals are responsible for leading the day-to-day management of the Portfolio:

• **Jed S. Fogdall**, Global Head of Portfolio Management, Chairman of the Investment Committee, Vice President, and Senior Portfolio Manager of the Advisor, has been a portfolio manager of the Portfolio since 2012.

• **John A. Hertzer**, Vice President and Senior Portfolio Manager of the Advisor, has been a portfolio manager of the Portfolio since 2022.

• **Allen Pu,** Deputy Head of Portfolio Management, North America, member of the Investment Committee, Vice President, and Senior Portfolio Manager of the Advisor, has been a portfolio manager of the Portfolio since 2024.

Purchase and Sale of Shares

The Portfolio issues (or redeems) ETF Class shares at NAV only to certain financial institutions that have entered into agreements with the Portfolio's distributor in large aggregated blocks known as "Creation Units." A Creation Unit of the Portfolio's ETF Class shares consists of 25,000 shares. Creation Units are issued (or redeemed) in-kind for securities (and an amount of cash) that the Portfolio specifies each day at the NAV next determined after receipt of an order.

<br> 8 Dimensional Fund Advisors

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**Individual ETF Class shares of the Portfolio may only be purchased and sold on NYSE Arca, Inc., other national securities exchanges, electronic crossing networks and other alternative trading systems through your broker-dealer at market prices and are not individually redeemable from the Portfolio.** An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares (bid) and the lowest price a seller is willing to accept for shares (ask) when buying or selling shares in the secondary market (the "bid-ask spread"). Because the Portfolio's ETF Class shares trade at market prices rather than at NAV, ETF Class shares may trade at a price less than (discount) or greater than (premium) the NAV of the ETF Class shares. Recent information, including information on the ETF Class shares' NAV, market price, premiums and discounts, and bid-ask spreads, is available on the Portfolio's website at https://www.dimensional.com/us-en/funds.

Tax Information

The dividends and distributions you receive from the Portfolio are taxable and generally will be taxed as ordinary income, capital gains, or some combination of both, unless you are investing through a tax-advantaged arrangement, such as a 401(k) plan or an individual retirement account, in which case distributions may be taxed as ordinary income when withdrawn from the plan or account.

Payments to Financial Intermediaries

If you purchase the Portfolio through a broker-dealer or other financial intermediary (such as a bank), the Portfolio and its related companies may pay the intermediary for the sale of the Portfolio shares and/or related services. These payments may create a conflict of interest by influencing the financial intermediary to recommend the Portfolio over another investment. Ask your financial advisor or visit your financial intermediary's website for more information.

<br> U.S. Core Equity 1 Portfolio 9

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| **Dimensional Fund Advisors LP<br>6300 Bee Cave Road, Building One <br>Austin, TX 78746 <br>(512) 306-7400**  | ![](img_a2eddfcf7e334f1.jpg) |
| DFA-022826-DSEO | ![](img_a2eddfcf7e334f1.jpg) |

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