# EDGAR Filing Document

**Accession Number:** 0001120924
**File Stem:** 0001741773-23-000542
**Filing Date:** 2023-2
**Character Count:** 40743
**Document Hash:** beb144700dfc4d2657e729865813cf36
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001741773-23-000542.hdr.sgml**: 20230228

**ACCESSION NUMBER**: 0001741773-23-000542

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 6

**FILED AS OF DATE**: 20230228

**DATE AS OF CHANGE**: 20230228

**EFFECTIVENESS DATE**: 20230228

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** T. Rowe Price QM U.S. Bond Index Fund, Inc.
- **CENTRAL INDEX KEY:** 0001120924
- **IRS NUMBER:** 522273334
- **STATE OF INCORPORATION:** MD
- **FISCAL YEAR END:** 1031

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-45018
- **FILM NUMBER:** 23678533

**BUSINESS ADDRESS:**
- **STREET 1:** 100 EAST PRATT STREET
- **CITY:** BALTIMORE
- **STATE:** MD
- **ZIP:** 21202
- **BUSINESS PHONE:** 410-345-2000

**MAIL ADDRESS:**
- **STREET 1:** 100 EAST PRATT STREET
- **CITY:** BALTIMORE
- **STATE:** MD
- **ZIP:** 21202

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** T. Rowe Price U.S. Bond Enhanced Index Fund, Inc.
- **DATE OF NAME CHANGE:** 20110509

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** T. Rowe Price U.S. Bond Index Fund, Inc.
- **DATE OF NAME CHANGE:** 20051028

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** T ROWE PRICE US BOND INDEX FUND INC
- **DATE OF NAME CHANGE:** 20000802

## Series and Classes Contracts Data

### T. Rowe Price QM U.S. Bond Index Fund (Series ID: S000002166)

| Class ID   | Class Name                                    | Ticker Symbol   |
|:---|:---|:---|
| C000005563 | T. Rowe Price QM U.S. Bond Index Fund         | PBDIX           |
| C000222342 | T. Rowe Price QM U.S. Bond Index Fund-Z Class | TSBZX           |
| C000222343 | T. Rowe Price QM U.S. Bond Index Fund-I Class | TSBLX           |

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| | |
|:---|:---|
| ![](img_06c0a0d4adeb4f1.jpg) | ![](img_ee4e711ee2974f1.jpg) |
| **SUMMARY PROSPECTUS**<br>March 1, 2023 | **SUMMARY PROSPECTUS**<br>March 1, 2023 |
|  | T. ROWE PRICE |
|  | **QM U.S. Bond Index Fund** |
| &nbsp;&nbsp;&nbsp;&nbsp;PBDIX<br>TSBLX<br>TSBZX | &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Investor Class<br>I Class<br>Z Class |
| The Securities and Exchange Commission (SEC) has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.<br>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, shareholder reports, and other information about the fund online at **troweprice.com/prospectus**. You can also get this information at no cost by calling **1-800-638-5660**, by sending an e-mail request to **info@troweprice.com**, or by contacting your financial intermediary. This Summary Prospectus incorporates by reference the fund's prospectus, dated March 1, 2023, as amended or supplemented, and Statement of Additional Information, dated March 1, 2023, as amended or supplemented. | The Securities and Exchange Commission (SEC) has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.<br>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, shareholder reports, and other information about the fund online at **troweprice.com/prospectus**. You can also get this information at no cost by calling **1-800-638-5660**, by sending an e-mail request to **info@troweprice.com**, or by contacting your financial intermediary. This Summary Prospectus incorporates by reference the fund's prospectus, dated March 1, 2023, as amended or supplemented, and Statement of Additional Information, dated March 1, 2023, as amended or supplemented. |
|  | ![](img_7613b4df48a24f1.jpg) |

---

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**SUMMARY**<sub>1</sub>

#### Investment Objective(s)
The fund seeks to provide a total return that matches or incrementally exceeds the performance of the U.S. investment-grade bond market.

#### Fees and Expenses
This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the fund. **You may also incur brokerage commissions and other charges when buying or selling shares of the fund, which are not reflected in the table or example below.**

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| | | | | |
|:---|:---|:---|:---|:---|
| **Fees and Expenses of the Fund** | **Fees and Expenses of the Fund** |  |  |  |
|  |  | **Investor <br>Class** | **I <br>Class** | **Z <br>Class** |
| **Shareholder fees (fees paid directly from your investment)** | **Shareholder fees (fees paid directly from your investment)** | **Shareholder fees (fees paid directly from your investment)** | **Shareholder fees (fees paid directly from your investment)** | **Shareholder fees (fees paid directly from your investment)** |
| **Maximum account fee** | **Maximum account fee** | $20<br> <sup>a</sup>  |  |  |
| **Annual fund operating expenses <br>(expenses that you pay each year as a <br>percentage of the value of your investment)** | **Annual fund operating expenses <br>(expenses that you pay each year as a <br>percentage of the value of your investment)** | **Annual fund operating expenses <br>(expenses that you pay each year as a <br>percentage of the value of your investment)** | **Annual fund operating expenses <br>(expenses that you pay each year as a <br>percentage of the value of your investment)** | **Annual fund operating expenses <br>(expenses that you pay each year as a <br>percentage of the value of your investment)** |
| **Management fees** | **Management fees** | 0.07<br> **%** | 0.07<br> **%** | 0.07<br> **%** |
| **Other expenses** | **Other expenses** | 0.20 | 0.06<br> <sup>b</sup>  | 0.03 |
| **Total annual fund operating expenses** | **Total annual fund operating expenses** | 0.27 | 0.13 | 0.10 |
| **Fee waiver/expense reimbursement** | **Fee waiver/expense reimbursement** | **(0.02**)<sup>c</sup> | **(0.01**)<sup>b</sup> | **(0.10**)<sup>d</sup> |
| **Total annual fund operating expenses after fee <br>waiver/expense reimbursement** | **Total annual fund operating expenses after fee <br>waiver/expense reimbursement** | 0.25<br> **<sup>c</sup>**  | 0.12<br> **<sup>b</sup>**  | 0.00<br> **<sup>d</sup>**  |
| <sup>a</sup> | Subject to certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee. | Subject to certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee. | Subject to certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee. | Subject to certain exceptions, accounts with a balance of less than $10,000 are charged an annual $20 fee. |
| <sup>b</sup> | T. Rowe Price Associates, Inc., has contractually agreed (through February 28, 2025) to pay the operating expenses of the fund's I Class excluding management fees; interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses (I Class Operating Expenses), to the extent the I Class Operating Expenses exceed 0.05% of the class' average daily net assets. The agreement may only be terminated at any time after February 28, 2025, with approval by the fund's Board of Directors. Any expenses paid under this agreement (and any applicable prior limitations) are subject to reimbursement to T. Rowe Price Associates, Inc., by the class whenever the I Class Operating Expenses are below 0.05%. However, the class will not reimburse T. Rowe Price Associates, Inc., more than three years from the date such amounts were initially waived or paid. The class may only reimburse T. Rowe Price Associates, Inc., if the reimbursement does not cause the I Class Operating Expenses (after the reimbursement is taken into account) to exceed the current expense limitation on I Class Operating Expenses (or the expense limitation in place at the time the amounts were waived or paid). | T. Rowe Price Associates, Inc., has contractually agreed (through February 28, 2025) to pay the operating expenses of the fund's I Class excluding management fees; interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses (I Class Operating Expenses), to the extent the I Class Operating Expenses exceed 0.05% of the class' average daily net assets. The agreement may only be terminated at any time after February 28, 2025, with approval by the fund's Board of Directors. Any expenses paid under this agreement (and any applicable prior limitations) are subject to reimbursement to T. Rowe Price Associates, Inc., by the class whenever the I Class Operating Expenses are below 0.05%. However, the class will not reimburse T. Rowe Price Associates, Inc., more than three years from the date such amounts were initially waived or paid. The class may only reimburse T. Rowe Price Associates, Inc., if the reimbursement does not cause the I Class Operating Expenses (after the reimbursement is taken into account) to exceed the current expense limitation on I Class Operating Expenses (or the expense limitation in place at the time the amounts were waived or paid). | T. Rowe Price Associates, Inc., has contractually agreed (through February 28, 2025) to pay the operating expenses of the fund's I Class excluding management fees; interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses (I Class Operating Expenses), to the extent the I Class Operating Expenses exceed 0.05% of the class' average daily net assets. The agreement may only be terminated at any time after February 28, 2025, with approval by the fund's Board of Directors. Any expenses paid under this agreement (and any applicable prior limitations) are subject to reimbursement to T. Rowe Price Associates, Inc., by the class whenever the I Class Operating Expenses are below 0.05%. However, the class will not reimburse T. Rowe Price Associates, Inc., more than three years from the date such amounts were initially waived or paid. The class may only reimburse T. Rowe Price Associates, Inc., if the reimbursement does not cause the I Class Operating Expenses (after the reimbursement is taken into account) to exceed the current expense limitation on I Class Operating Expenses (or the expense limitation in place at the time the amounts were waived or paid). | T. Rowe Price Associates, Inc., has contractually agreed (through February 28, 2025) to pay the operating expenses of the fund's I Class excluding management fees; interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses (I Class Operating Expenses), to the extent the I Class Operating Expenses exceed 0.05% of the class' average daily net assets. The agreement may only be terminated at any time after February 28, 2025, with approval by the fund's Board of Directors. Any expenses paid under this agreement (and any applicable prior limitations) are subject to reimbursement to T. Rowe Price Associates, Inc., by the class whenever the I Class Operating Expenses are below 0.05%. However, the class will not reimburse T. Rowe Price Associates, Inc., more than three years from the date such amounts were initially waived or paid. The class may only reimburse T. Rowe Price Associates, Inc., if the reimbursement does not cause the I Class Operating Expenses (after the reimbursement is taken into account) to exceed the current expense limitation on I Class Operating Expenses (or the expense limitation in place at the time the amounts were waived or paid). |
| <sup>c</sup> | T. Rowe Price Associates, Inc., has contractually agreed (through February 28, 2025) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the class' ratio of expenses to average daily net assets to exceed 0.25%. The agreement may only be terminated at any time after February 28, 2025, with approval by the fund's Board of Directors. Fees waived and expenses paid under this agreement (and any applicable prior limitations) are subject to reimbursement to T. Rowe Price Associates, Inc., by the class whenever the class' expense ratio is below 0.25%. However, the class will not reimburse T. Rowe Price Associates, Inc., more than three years from the date such amounts were initially waived or paid. The class may only reimburse T. Rowe Price Associates, Inc., if the reimbursement does not cause the class' expense ratio (after the reimbursement is taken into account) to exceed the class' current expense limitation (or the expense limitation in place at the time the amounts were waived or paid). | T. Rowe Price Associates, Inc., has contractually agreed (through February 28, 2025) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the class' ratio of expenses to average daily net assets to exceed 0.25%. The agreement may only be terminated at any time after February 28, 2025, with approval by the fund's Board of Directors. Fees waived and expenses paid under this agreement (and any applicable prior limitations) are subject to reimbursement to T. Rowe Price Associates, Inc., by the class whenever the class' expense ratio is below 0.25%. However, the class will not reimburse T. Rowe Price Associates, Inc., more than three years from the date such amounts were initially waived or paid. The class may only reimburse T. Rowe Price Associates, Inc., if the reimbursement does not cause the class' expense ratio (after the reimbursement is taken into account) to exceed the class' current expense limitation (or the expense limitation in place at the time the amounts were waived or paid). | T. Rowe Price Associates, Inc., has contractually agreed (through February 28, 2025) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the class' ratio of expenses to average daily net assets to exceed 0.25%. The agreement may only be terminated at any time after February 28, 2025, with approval by the fund's Board of Directors. Fees waived and expenses paid under this agreement (and any applicable prior limitations) are subject to reimbursement to T. Rowe Price Associates, Inc., by the class whenever the class' expense ratio is below 0.25%. However, the class will not reimburse T. Rowe Price Associates, Inc., more than three years from the date such amounts were initially waived or paid. The class may only reimburse T. Rowe Price Associates, Inc., if the reimbursement does not cause the class' expense ratio (after the reimbursement is taken into account) to exceed the class' current expense limitation (or the expense limitation in place at the time the amounts were waived or paid). | T. Rowe Price Associates, Inc., has contractually agreed (through February 28, 2025) to waive its fees and/or bear any expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) that would cause the class' ratio of expenses to average daily net assets to exceed 0.25%. The agreement may only be terminated at any time after February 28, 2025, with approval by the fund's Board of Directors. Fees waived and expenses paid under this agreement (and any applicable prior limitations) are subject to reimbursement to T. Rowe Price Associates, Inc., by the class whenever the class' expense ratio is below 0.25%. However, the class will not reimburse T. Rowe Price Associates, Inc., more than three years from the date such amounts were initially waived or paid. The class may only reimburse T. Rowe Price Associates, Inc., if the reimbursement does not cause the class' expense ratio (after the reimbursement is taken into account) to exceed the class' current expense limitation (or the expense limitation in place at the time the amounts were waived or paid). |

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T. ROWE PRICE<sub>2</sub>

<sup>d</sup> T. Rowe Price Associates, Inc., has contractually agreed to waive and/or bear all the Z Class' expenses (excluding interest; expenses related to borrowings, taxes, and brokerage; nonrecurring, extraordinary expenses; and acquired fund fees and expenses) in their entirety. T. Rowe Price Associates, Inc., expects this fee waiver and/or expense reimbursement arrangement to remain in place indefinitely, and the agreement may only be amended or terminated with approval by the fund's Board of Directors.

**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, that your investment has a 5% return each year, and that the fund's operating expenses remain the same. The example also assumes that any current expense limitation arrangement remains in place for the period noted in the previous table; therefore, the figures have been adjusted to reflect fee waivers or expense reimbursements only in the periods for which the expense limitation arrangement is expected to continue. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

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| | | | | |
|:---|:---|:---|:---|:---|
|  | **1 Year** | **3 Years** | **5 Years** | **10 Years** |
| **Investor Class**  | $**26** | $**83** | $**148** | $**339** |
| **I Class**  | **12** | **40** | **71** | **164** |
| **Z Class**  | **0** | **0** | **0** | **0** |

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**Portfolio Turnover** The fund 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 the fund's shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 203.5% of the average value of its portfolio.

#### Investments, Risks, and Performance

#### Principal Investment Strategies
Under normal conditions, the fund invests at least 80% of its net assets (including any borrowings for investment purposes) in bonds that are held in its benchmark index. Consistent with the benchmark index, the fund's holdings will normally include U.S. government and agency obligations, mortgage- and asset-backed securities, corporate bonds, and U.S. dollar-denominated securities of foreign issuers.

The fund's overall investment strategy is to match or incrementally exceed the performance of the U.S. investment-grade bond market. To achieve this goal, the fund seeks to provide total returns (after all of the fund's expenses have been deducted) that match or incrementally exceed the total returns of its benchmark index, the Bloomberg U.S. Aggregate Bond Index (Index). The Index is a broadly diversified index that typically consists of investment-grade, fixed income instruments with intermediate- to long-term maturities. To be eligible for inclusion in the Index, a security must be U.S. dollar-denominated, rated investment grade, have a fixed rate coupon with at least $300 million or more of outstanding face value, and have one or more years remaining to maturity. The Index is market capitalization weighted and the securities represented in the Index are updated on the last business day of each month. The

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**SUMMARY**<sub>3</sub>

composition of the Index is rebalanced at each month-end and represents the fixed set of securities on which index returns are calculated for the next month. As of December 31, 2022, there were 13,184 securities in the Index. For the last five years ended June 30, 2022, the weighted average maturity of the Index ranged from 7.7 years to 8.7 years, although this range will vary with market conditions. As of December 31, 2022, the fund's weighted average maturity was 8.4 years.

The adviser does not attempt to fully replicate the Index, but generally invests in a wide range of bonds represented in the Index. While the fund's portfolio is structured to have a similar overall risk profile and other characteristics to the fund's Index, the portfolio manager may adjust certain holdings in relation to their weighting in the Index and rely on quantitative models (as indicated by the "QM" in the fund's name) in an attempt to generate a modest amount of outperformance over the Index. These quantitative models are designed to help replicate the overall risk factors and other characteristics of the Index in a more efficient manner and to inform overweighting and underweighting of sub-sectors relative to the Index, which are designed in part to provide performance that incrementally exceeds that of the Index. In conjunction with the quantitative models, the portfolio manager evaluates specific traits and sectors within the Index and, within each broad segment of the Index (such as corporate bonds, U.S. government securities, and asset- and mortgage-backed securities), selects a set of U.S. dollar-denominated bonds that represents key benchmark traits. The most important of these traits are interest rate sensitivity, credit quality, and sector diversification, although other characteristics may be considered.

Based on the portfolio manager's evaluation of quantitative models, and views as to the relative value or attractiveness of a specific trait or sector, the fund places a slightly greater or lesser emphasis on certain index characteristics than their representation in the Index. This could result in the fund being underweight or overweight in certain sectors versus the Index or having a duration that differs from that of the Index. Duration, which is expressed in years, is a calculation that attempts to measure the price sensitivity of a bond or bond fund to changes in interest rates. For example, the price of a bond fund with a duration of three years would be expected to fall approximately 3% if interest rates rose by one percentage point. A bond fund with a longer duration should be more sensitive to changes in interest rates than a bond fund with a shorter duration.

As a means of adjusting the fund's duration and gaining exposure to investment-grade bonds, the fund buys and sells U.S Treasury futures, as well as mortgage-backed securities on a delayed delivery or forward commitment basis through the "to-be-announced" (TBA) market. U.S. Treasury futures are futures contracts collateralized by U.S. Treasury bonds or notes. With TBA transactions, the particular mortgage-backed securities to be delivered are not identified at the trade date, but the delivered securities must meet specified terms and standards. In an effort to obtain underlying mortgage-backed securities on more preferable terms or to enhance returns, the fund may extend the settlement by entering into "dollar roll" transactions in which the fund sells mortgage-backed securities and simultaneously agrees to purchase substantially similar securities on a future date.

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T. ROWE PRICE<sub>4</sub>

#### Principal Risks
As with any fund, there is no guarantee that the fund will achieve its objective(s). The fund's share price fluctuates, which means you could lose money by investing in the fund. The principal risks of investing in this fund, which may be even greater in bad or uncertain market conditions, are summarized as follows:

**Fixed income markets** Economic and other market developments can adversely affect the fixed income securities markets. At times, participants in these markets may develop concerns about the ability of certain issuers of debt instruments to make timely principal and interest payments, or they may develop concerns about the ability of financial institutions that make markets in certain debt instruments to facilitate an orderly market. Those concerns could cause increased volatility and reduced liquidity in particular securities or in the overall fixed income markets and the related derivatives markets. A lack of liquidity or other adverse credit market conditions may hamper the fund's ability to sell the debt instruments in which it invests or to find and purchase suitable debt instruments.

**Market conditions** The value of the fund's investments may decrease, sometimes rapidly or unexpectedly, due to factors affecting an issuer held by the fund, particular industries, or the overall securities markets. A variety of factors can increase the volatility of the fund's holdings and markets generally, including political or regulatory developments, recessions, inflation, rapid interest rate changes, war, military conflict, or acts of terrorism, natural disasters, and outbreaks of infectious illnesses or other widespread public health issues such as the coronavirus pandemic and related governmental and public responses (including sanctions). Certain events may cause instability across global markets, including reduced liquidity and disruptions in trading markets, while some events may affect certain geographic regions, countries, sectors, and industries more significantly than others. Government intervention in markets may impact interest rates, market volatility, and security pricing. These adverse developments may cause broad declines in market value due to short-term market movements or for significantly longer periods during more prolonged market downturns.

**Index investing** Although the adviser seeks to match or incrementally exceed the performance of the fund's benchmark index using quantitative models and the analysis of specific metrics to construct the fund's portfolio, holdings are generally not reallocated based on changes in market conditions or outlook for a specific security, industry, or market sector.

**Tracking error** The fund's attempt to achieve an incremental return above the index could result in a greater chance of tracking error when compared with a fund that strictly follows a passive indexing strategy. Index funds are generally subject to the risk that their returns will be slightly below the returns of the index they are designed to track (referred to as "tracking error") because the funds incur fees and transaction expenses while the index has no fees or expenses. The fund may experience tracking error due to changes in the composition of the index or the timing of purchases and redemptions of fund shares, or because it does not attempt to fully replicate its benchmark index. In addition, relying on quantitative models entails the risk that the models may be limited or incorrect, the data on which the models rely may be incorrect or incomplete, or the models may not be implemented as intended by the adviser, all of which could increase the fund's tracking error.

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**SUMMARY**<sub>5</sub>

**Portfolio management** Although the fund seeks to closely track its benchmark index, the reliance on quantitative models and overweighting and underweighting of certain sectors by the fund's investment adviser may cause the fund to underperform similar index funds.

**Interest rates** The prices of, and the income generated by, debt instruments held by the fund may be affected by changes in interest rates. A rise in interest rates typically causes the price of a fixed rate debt instrument to fall and its yield to rise. Conversely, a decline in interest rates typically causes the price of a fixed rate debt instrument to rise and the yield to fall. The prices and yields of inflation-linked bonds are directly impacted by the rate of inflation as well as changes in interest rates. Generally, funds with longer weighted average maturities and durations carry greater interest rate risk. Changes in monetary policy made by central banks and/or governments, such as the discontinuation and replacement of benchmark rates, are likely to affect the interest rates or yields of the securities in which the fund invests.

**Prepayments and extensions** The fund is subject to prepayment risks because the principal on mortgage-backed securities, asset-backed securities, or any debt instrument with an embedded call option may be prepaid at any time, which could reduce the security's yield and market value. The rate of prepayments tends to increase as interest rates fall, which could cause the average maturity of the portfolio to shorten. Extension risk may result from a rise in interest rates, which tends to make mortgage-backed securities, asset-backed securities, and other callable debt instruments more volatile.

**Credit quality** An issuer of a debt instrument could suffer an adverse change in financial condition that results in a payment default (failure to make scheduled interest or principal payments), rating downgrade, or inability to meet a financial obligation. Securities that are rated below investment grade carry greater risk of default and should be considered speculative.

**Liquidity** The fund may not be able to meet requests to redeem shares issued by the fund without significant dilution of the remaining shareholders' interests in the fund. In addition, the fund may not be able to sell a holding in a timely manner at a desired price. Reduced liquidity in the bond markets can result from a number of events, such as limited trading activity, reductions in bond inventory, and rapid or unexpected changes in interest rates. Markets with lower overall liquidity could lead to greater price volatility and limit the fund's ability to sell a holding at a suitable price.

**TBAs and dollar rolls** Although the securities that are delivered in TBA transactions must meet certain standards, there is a risk that the actual securities received by the fund may be less favorable than what was anticipated when entering into the transaction. TBA transactions are collateralized but they still involve the risk that a counterparty will fail to deliver the security, exposing the fund to potential losses. Whether or not the fund takes delivery of the securities at the termination date of a TBA transaction, it will nonetheless be exposed to changes in the value of the underlying investments during the term of the agreement. Forward settling securities, such as TBAs, involve leverage which may magnify investment risks and can cause losses to be realized more quickly. In addition, the fund's portfolio turnover rate and transaction costs are increased when the fund enters into dollar roll transactions.

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T. ROWE PRICE<sub>6</sub>

**Portfolio turnover** High portfolio turnover may adversely affect the fund's performance and increase transaction costs, which could increase the fund's expenses. High portfolio turnover may also result in the distribution of higher capital gains when compared with a fund with less active trading policies, which could have an adverse tax impact if the fund's shares are held in a taxable account.

**Derivatives** To the extent the fund uses derivatives, including, without limitation, futures, forwards, options, structured securities, or swaps, it is exposed to additional volatility and potential losses. A derivative involves risks different from, and possibly greater than, the risks associated with investing directly in the assets on which the derivative is based. Derivatives can be highly volatile, illiquid, and difficult to value, and changes in the value of a derivative may not properly correlate with changes in the value of the underlying asset, reference rate, or index. The fund could be exposed to significant losses if it is unable to close a derivatives position due to the lack of a liquid secondary trading market. Changes in the value of a derivative or other similar instrument may also create margin delivery or settlement payment obligations for the fund. Derivatives may involve the risk that a counterparty to the derivatives agreement will fail to make required payments or comply with the terms of the agreement. There is also the possibility that limitations or trading restrictions may be imposed by an exchange or government regulation.

**Cybersecurity breaches** The fund could be harmed by intentional cyberattacks and other cybersecurity breaches, including unauthorized access to the fund's assets, customer data and confidential shareholder information, or other proprietary information. In addition, a cybersecurity breach could cause one of the fund's service providers or financial intermediaries to suffer unauthorized data access, data corruption, or loss of operational functionality.

#### Performance
The following performance information provides some indication of the risks of investing in the fund. The fund's performance information represents only past performance (before and after taxes) and is not necessarily an indication of future results.

The following bar chart illustrates how much returns can differ from year to year by showing calendar year returns and the best and worst calendar quarter returns during those years for the fund's Investor Class. Returns for other share classes vary since they have different expenses.

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**SUMMARY**<sub>7</sub>

**QM U.S. BOND INDEX FUND**<br>

Calendar Year Returns

![PerformanceBarChartData(2013:-2.18, 2014:6.12, 2015:0.3, 2016:2.69, 2017:3.82, 2018:-0.01, 2019:8.54, 2020:8.15, 2021:-1.45, 2022:-13.64)](img_acd0b74b86c84f1.jpg)

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
|  | Quarter Ended | Total Return |  | Quarter Ended | Total Return |
| Best Quarter | 6/30/20 | 3.96% | Worst Quarter | 3/31/22 | -5.89% |

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The following table shows the average annual total returns for each class of the fund that has been in operation for at least one full calendar year, and also compares the returns with the returns of a relevant broad-based market index, as well as with the returns of one or more comparative indexes that have investment characteristics similar to those of the fund, if applicable.

In addition, the table shows hypothetical after-tax returns to demonstrate how taxes paid by a shareholder may influence returns. 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 an investor's tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as a 401(k) account or an IRA.

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T. ROWE PRICE<sub>8</sub>

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
| **Average Annual Total Returns** | **Average Annual Total Returns** | **Average Annual Total Returns** | **Average Annual Total Returns** |  |  |
|  | **Periods ended** | **Periods ended** | **Periods ended** | **Periods ended** | **Periods ended** |
|  | **December 31, 2022** | **December 31, 2022** | **December 31, 2022** | **December 31, 2022** | **December 31, 2022** |
|  |  |  |  | **Since** | **Inception** |
|  | **1 Year**  | **5 Years**  | **10 Years**  | **inception** | **date** |
| **Investor Class** |  |  |  |  | **11/30/2000** |
| **Returns before taxes** | **-13.64%** | **-0.02%** | 1.04 <br>**%** | **— %** |  |
| **Returns after taxes on distributions** | **-14.55**  | **-1.12**  | **-0.16**  | **—**  |  |
| **Returns after taxes on distributions and sale** |  |  |  |  |  |
| **of fund shares** | **-8.05**  | **-0.41**  | 0.31  | **—**  |  |
| **I Class** |  |  |  |  | **10/05/2020** |
| **Returns before taxes** | **-13.51**  | **—**  | **—**  | **-6.31** |  |
| **Z Class** |  |  |  |  | **10/05/2020** |
| **Returns before taxes** | **-13.42**  | **—**  | **—**  | **-6.25** |  |
| **Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses, or taxes)** | **Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses, or taxes)** | **Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses, or taxes)** | **Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses, or taxes)** | **Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses, or taxes)** |  |
|  | **-13.01**  | 0.02  | 1.06  | **-6.28**<br> **<sup>a</sup>**  |  |
| **Lipper Core Bond Funds Average** | **Lipper Core Bond Funds Average** | **Lipper Core Bond Funds Average** | **Lipper Core Bond Funds Average** | **Lipper Core Bond Funds Average** |  |
|  | **-13.51**  | **-0.04**  | 0.99  | **-6.20**<br> **<sup>b</sup>**  |  |

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a Return since 10/5/20.

b Return since 9/30/20.

Updated performance information is available through troweprice.com.

#### Management
**Investment Adviser** T. Rowe Price Associates, Inc. (T. Rowe Price or Price Associates)

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| | | | |
|:---|:---|:---|:---|
| **Portfolio Manager** | **Title** | **Managed<br>Fund<br>Since** | **Joined<br>Investment<br>Adviser** |
| **Robert M. Larkins** | **Chair of Investment**<br>**Advisory Committee** | **2007** | **2003** |

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#### Purchase and Sale of Fund Shares
The Investor Class generally requires a $2,500 minimum initial investment ($1,000 minimum initial investment if opening an IRA, a custodial account for a minor, or a small business retirement plan account). Additional purchases generally require a $100 minimum. These investment minimums generally are waived for financial intermediaries and certain employer-sponsored retirement plans submitting orders on behalf of their customers.

The I Class requires a $500,000 minimum initial investment per fund per account registration, although the initial investment minimum generally is waived or reduced for financial intermediaries, eligible retirement plans, certain client accounts for which T. Rowe Price or its affiliate has discretionary investment authority, qualifying directly held accounts, and certain other types of accounts.

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**SUMMARY**<sub>9</sub>

The Z Class is only available to funds managed by T. Rowe Price and other advisory clients of T. Rowe Price or its affiliates that are subject to a contractual fee for investment management services. There is no minimum initial investment and no minimum for additional purchases.

For investors holding shares of the fund directly with T. Rowe Price, you may purchase, redeem, or exchange fund shares by mail; by telephone (1-800-225-5132 for IRAs and nonretirement accounts; 1-800-492-7670 for small business retirement plans; and 1-800-638-8790 for institutional investors and financial intermediaries); or, for certain accounts, by accessing your account online through troweprice.com.

If you hold shares through a financial intermediary or retirement plan, you must purchase, redeem, and exchange shares of the fund through your intermediary or retirement plan. You should check with your intermediary or retirement plan to determine the investment minimums that apply to your account.

#### Tax Information
The fund declares dividends, if any, daily and pays them on the first business day of each month. Any capital gains are declared and paid annually, usually in December. Redemptions or exchanges of fund shares and distributions by the fund, whether or not you reinvest these amounts in additional fund shares, generally may be taxed as ordinary income or capital gains unless you invest through a tax-deferred account (in which case you will be taxed upon withdrawal from such account).

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

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|:---|:---|
| ![](img_6948fe6c97084f1.jpg) |  |
| T. Rowe Price Associates, Inc.<br>100 East Pratt Street<br>Baltimore, MD 21202 | F134-045 3/1/23 |

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