# EDGAR Filing Document

**Accession Number:** 0000746458
**File Stem:** 0000746458-25-000018
**Filing Date:** 2025-9
**Character Count:** 21766
**Document Hash:** b698f0f3c30003a9d7613a9705f28bba
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000746458-25-000018.hdr.sgml**: 20250926

**ACCESSION NUMBER**: 0000746458-25-000018

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 3

**FILED AS OF DATE**: 20250926

**DATE AS OF CHANGE**: 20250926

**EFFECTIVENESS DATE**: 20250926

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** AMERICAN CENTURY MUNICIPAL TRUST
- **CENTRAL INDEX KEY:** 0000746458

**ORGANIZATION NAME:**
- **EIN:** 776009794
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 0531

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 002-91229
- **FILM NUMBER:** 251349519

**BUSINESS ADDRESS:**
- **STREET 1:** 4500 MAIN STREET
- **CITY:** KANSAS CITY
- **STATE:** MO
- **ZIP:** 64111
- **BUSINESS PHONE:** 816-531-5575

**MAIL ADDRESS:**
- **STREET 1:** 4500 MAIN STREET
- **CITY:** KANSAS CITY
- **STATE:** MO
- **ZIP:** 64111

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** BENHAM MUNICIPAL TRUST
- **DATE OF NAME CHANGE:** 19940202

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** BENHAM NATIONAL TAX FREE TRUST
- **DATE OF NAME CHANGE:** 19920703

## Series and Classes Contracts Data

### INTERMEDIATE-TERM TAX-FREE BOND FUND (Series ID: S000006472)

| Class ID   | Class Name     | Ticker Symbol   |
|:---|:---|:---|
| C000017689 | INVESTOR CLASS | TWTIX           |
| C000017691 | I CLASS        | AXBIX           |
| C000088013 | A CLASS        | TWWOX           |
| C000088014 | C CLASS        | TWTCX           |
| C000189767 | Y CLASS        | ATBYX           |

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| | | | |
|:---|:---|:---|:---|
| **Summary Prospectus&nbsp;&nbsp;&nbsp;&nbsp;** October 1, 2025<br>**American Century Investments**<sup>®</sup><br>**Intermediate-Term Tax-Free Bond Fund** | **Summary Prospectus&nbsp;&nbsp;&nbsp;&nbsp;** October 1, 2025<br>**American Century Investments**<sup>®</sup><br>**Intermediate-Term Tax-Free Bond Fund** | **Summary Prospectus&nbsp;&nbsp;&nbsp;&nbsp;** October 1, 2025<br>**American Century Investments**<sup>®</sup><br>**Intermediate-Term Tax-Free Bond Fund** | ![newaci_logoblkf44.jpg](newaci_logoblkf44.jpg) |
| **Investor Class:** TWTIX<br>**I Class:** AXBIX | **Y Class:** ATBYX<br>**A Class:** TWWOX | **C Class:** TWTCX |  |

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| | |
|:---|:---|
| 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, reports to shareholders, and other information about the fund online at the web addresses listed below. You can also get this information at no cost by calling or sending an email request. The fund's prospectus and other information are also available from financial intermediaries (such as banks and broker-dealers) through which shares of the fund may be purchased or sold.  | 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, reports to shareholders, and other information about the fund online at the web addresses listed below. You can also get this information at no cost by calling or sending an email request. The fund's prospectus and other information are also available from financial intermediaries (such as banks and broker-dealers) through which shares of the fund may be purchased or sold.  |
| &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**Retail Investors**<br>americancentury.com/docs<br>1-800-345-2021 or 816-531-5575<br>prospectus@americancentury.com | **Financial Professionals**<br>americancentury.com/fadocs<br>1-800-345-6488<br>advisor_prospectus@americancentury.com |
| This summary prospectus incorporates by reference the fund's <u>[prospectus and statement of additional information](https://www.sec.gov/Archives/edgar/data/746458/000074645825000012/ck0000746458-20250926.htm)</u> (SAI), each dated October 1, 2025 (as supplemented at the time you receive this summary prospectus), as well as the Report of Independent Registered Public Accounting Firm and the financial statements included in the fund's Form N-CSR for the fiscal year ended May 31, 2025. The fund's SAI and <u>[Form N-CSR](https://www.sec.gov/Archives/edgar/data/746458/000074645825000006/ck0000746458-20250531.htm)</u> may be obtained, free of charge, in the same manner as the prospectus. | This summary prospectus incorporates by reference the fund's <u>[prospectus and statement of additional information](https://www.sec.gov/Archives/edgar/data/746458/000074645825000012/ck0000746458-20250926.htm)</u> (SAI), each dated October 1, 2025 (as supplemented at the time you receive this summary prospectus), as well as the Report of Independent Registered Public Accounting Firm and the financial statements included in the fund's Form N-CSR for the fiscal year ended May 31, 2025. The fund's SAI and <u>[Form N-CSR](https://www.sec.gov/Archives/edgar/data/746458/000074645825000006/ck0000746458-20250531.htm)</u> may be obtained, free of charge, in the same manner as the prospectus. |

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**Investment Objective**

The fund seeks safety of principal and high current income that is exempt from federal income tax.

**Fees and Expenses**

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the fund. You may also pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $100,000 in American Century Investments funds. More information about these and other discounts is available from your financial professional and in *Calculation of Sales Charges* on page 12 of the fund's prospectus, *Appendix A* of the fund's prospectus and *Sales Charges* in *Appendix B* of the statement of additional information.

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
| **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) | **Shareholder Fees** (fees paid directly from your investment) |
|  | *Investor* | *I* | *Y* | *A* | *C* |
| Maximum Sales Charge (Load) Imposed on<br>Purchases (as a percentage of offering price) |  |  |  | 4.50% |  |
| Maximum Deferred Sales Charge (Load)<br>(as a percentage of the lower of the original<br>offering price or redemption proceeds when<br>redeemed within one year of purchase) |  |  |  | None¹ | 1.00% |
| Maximum Annual Account Maintenance Fee<br>(waived if eligible investments total at least $25,000 or shareholder has elected electronic delivery) | $25 |  |  |  |  |

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
| **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) |
|  | *Investor* | *I* | *Y* | *A* | *C* |
| Management Fee | 0.46% | 0.26% | 0.23% | 0.46% | 0.46% |
| Distribution and Service (12b-1) Fees |  |  |  | 0.25% | 1.00% |
| Other Expenses | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% |
| Total Annual Fund Operating Expenses | 0.46% | 0.26% | 0.23% | 0.71% | 1.46% |

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<sup>1</sup> <sup>&nbsp;&nbsp;&nbsp;&nbsp;</sup>*Purchases of $1 million or more may be subject to a contingent deferred sales charge of 1.00% if the shares are redeemed within one year of the date of the purchase.*

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**Example**

The example below is intended to help you compare the costs of investing in the fund with the costs 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 you earn a 5% return each year, and that the fund's operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

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| | | | | |
|:---|:---|:---|:---|:---|
|  | *1 year* | *3 years* | *5 years* | *10 years* |
| Investor Class | $47 | $148 | $258 | $580 |
| I Class | $27 | $84 | $147 | $331 |
| Y Class | $24 | $74 | $130 | $293 |
| A Class | $519 | $667 | $828 | $1293 |
| C Class | $149 | $462 | $798 | $1542 |

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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 fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 45% of the average value of its portfolio.

**Principal Investment Strategies**

The portfolio managers principally buy investment-grade debt securities and, under normal market conditions, will invest at least 80% of the fund's net assets in debt securities with interest payments exempt from federal income tax. The fund's weighted average maturity will be not less than three years nor more than ten years. However, there is no maturity limit on individual securities.

The portfolio managers also may buy investment-grade debt securities with interest payments exempt from regular federal income tax, but not exempt from the federal alternative minimum tax. No more than 20% of the fund's assets may be invested in these securities.

Although the fund invests principally in investment-grade securities, up to 20% of the value of the fund's net assets may be invested in below investment-grade securities, also known as junk bonds. The fund also may invest in securities which, while not rated, are determined by the portfolio managers to be of comparable credit quality to those rated below investment-grade.

When determining whether to sell a security, portfolio managers consider, among other things, current and anticipated changes in interest rates, the credit quality of a particular issuer, comparable alternatives, general market conditions and any other factor deemed relevant by the portfolio managers.

**Principal Risks**

• **Credit Risk** – Debt securities, even investment-grade debt securities, are subject to credit risk. Credit risk is the risk that the inability or perceived inability of the issuer to make interest and principal payments will cause the value of the securities to decrease. As a result, the fund's share price could also decrease. Changes in the credit rating of a debt security held by the fund could have a similar effect.

• **Below Investment-Grade Securities Risk** – Issuers of lower rated, high yield securities are more vulnerable to real or perceived economic changes (such as an economic downturn or a prolonged period of rising interest rates), political changes or adverse developments specific to an issuer. These factors may be more likely to cause an issuer of low quality bonds to default on its obligations.

• **Interest Rate Risk** – Investments in debt securities are also sensitive to interest rate changes. Generally, the value of debt securities and the funds that hold them decline as interest rates rise. The fund's interest rate risk is moderate under normal market conditions, but it may fluctuate as the portfolio managers reposition the fund in response to changing market conditions. A period of rising interest rates may negatively affect the fund's performance.

• **Municipal Securities Risk** – The fund invests principally in municipal securities and will be sensitive to events that affect municipal markets, including legislative or political changes and the financial condition of the issuers of municipal securities. By investing primarily in municipal securities, the fund may have a higher level of risk than funds that invest in a larger universe of securities.

• **Loss of Tax-Exemptions Risk** – There is no guarantee that all of the fund's income will be exempt from federal or state income taxes. Income from municipal bonds held by the fund could be declared taxable because of unfavorable changes in tax laws, adverse interpretations by the Internal Revenue Service or state tax authorities, or noncompliant conduct of a bond issuer. The fund may sell securities that lose their tax-exempt statuses at inopportune times, which may cause tax consequences or a decrease in the fund's value.

• **Liquidity Risk** – The fund may also be subject to liquidity risk. During periods of market turbulence or unusually low trading activity, in order to meet redemptions it may be necessary for the fund to sell securities at prices that could have an adverse effect on the fund's share price. Changing regulatory and market conditions, including increases in interest rates and credit spreads may adversely affect the liquidity of the fund's investments.

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• **Market Risk** – The value of securities owned by the fund may go up and down, sometimes rapidly or unpredictably. Market risks, including political, regulatory, economic and social developments, can affect the value of the fund's investments. Natural disasters, public health emergencies, war, terrorism and other unforeseeable events may lead to increased market volatility and may have adverse long-term effects on world economies and markets generally.

• **Principal Loss Risk** – At any given time your shares may be worth less than the price you paid for them. In other words, it is possible to lose money by investing in the fund.

An investment in the fund is not a bank deposit, and it is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.

**Fund Performance**

The following bar chart and table provide some indication of the risks of investing in the fund. The bar chart shows changes in the fund's performance from year to year for Investor Class shares. The table shows how the fund's average annual returns for the periods shown compared with those of a broad measure of market performance. The table also shows returns for the S&P Intermediate Term National AMT-Free Municipal Bond Index, which the advisor considers to be more representative of the fund's investment strategy. The fund's past performance (before and after taxes) is not necessarily an indication of how the fund will perform in the future. For current performance information, including yields, please visit americancentury.com.

Sales charges and account fees, if applicable, are not reflected in the bar chart. If those charges were included, returns would be less than those shown.

**Calendar Year Total Returns**

![chart-b53f80cbf1824edd8cea.jpg](chart-b53f80cbf1824edd8cea.jpg)

**Highest Performance Quarter (4Q 2023): 6.58%&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Lowest Performance Quarter (1Q 2022): -5.40%** 

**As of June 30, 2025, the most recent calendar quarter end, the fund's Investor Class year-to-date return was 0.27%.**

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
| **Average Annual Total Returns**<br>*For the year ended December 31, 2024* | *1 year* | *5 years* | *10 years* | *Since*<br>*Inception*  | *Inception*<br>*Date*  |
| **Investor Class** Return Before Taxes | 1.65% | 1.07% | 1.97% |  | 03/02/1987 |
| &nbsp;&nbsp;&nbsp;Return After Taxes on Distributions | 1.65% | 1.08% | 1.97% |  | 03/02/1987 |
| &nbsp;&nbsp;&nbsp;Return After Taxes on Distributions and Sale of Fund Shares | 2.30% | 1.44% | 2.12% |  | 03/02/1987 |
| **I Class** Return Before Taxes | 1.86% | 1.26% | 2.17% |  | 04/15/2003 |
| **Y Class** Return Before Taxes | 1.89% | 1.29% |  | 2.27% | 04/10/2017 |
| **A Class** Return Before Taxes | -3.16% | -0.12% | 1.25% |  | 03/01/2010 |
| **C Class**<sup>1</sup> Return Before Taxes | 0.64% | 0.05% | 1.10% |  | 03/01/2010 |
| &nbsp;&nbsp;&nbsp;S&P National AMT-Free Municipal Bond Index<br>(reflects no deduction for fees, expenses or taxes) | 1.32% | 1.07% | 2.23% |  |  |
| &nbsp;&nbsp;&nbsp;S&P Intermediate Term National AMT-Free Municipal Bond Index<br>(reflects no deduction for fees, expenses or taxes)  | 1.22% | 1.19% | 2.07% |  |  |

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<sup>1</sup>*C Class shares automatically convert to A Class shares after approximately eight years. All returns for periods greater than eight years reflect this conversion.*

The after-tax returns are shown only for Investor Class shares. After-tax returns for other share classes will vary. 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 are not relevant to investors who hold their fund shares through tax-deferred arrangements, such as 401(k) plans or IRAs.

**Portfolio Management**

**Investment Advisor**

American Century Investment Management, Inc.

**Portfolio Managers**

**Alan Kruss**, Vice President and Portfolio Manager, has served on teams managing fixed-income investments for American Century Investments since joining the advisor in 1997.

**Joseph Gotelli**, Vice President and Senior Portfolio Manager, has served on teams managing fixed-income investments for American Century Investments since joining the advisor in 2008.

**Purchase and Sale of Fund Shares**

You may purchase or redeem shares of the fund on any business day through our website at americancentury.com, in person (at one of our Investor Centers), by mail (American Century Investments, P.O. Box 419200, Kansas City, MO 64141-6200), by telephone at 1-800-345-2021 (Investor Services Representative) or 1-800-345-3533 (Business, Not-For-Profit and Employer-Sponsored Retirement Plans), or through a financial intermediary. Shares may be purchased and redemption proceeds received by electronic bank transfer, by check or by wire.

Unless otherwise specified below, the minimum initial investment amount to open an account is $2,500 ($1,000 for Coverdell Education Savings Accounts and IRAs). However, American Century Investments will waive the fund minimum if you make an initial investment of at least $500 and continue to make automatic investments of at least $100 a month until reaching the fund minimum. Investors opening accounts through financial intermediaries may open an account with $250 for Investor, A and C Classes, but the financial intermediaries may require their clients to meet different investment minimums. The minimum may be waived for broker-dealer sponsored wrap program accounts, fee based accounts, and accounts through bank/trust and wealth management advisory organizations.

The minimum initial investment amount for the I Class is generally $5 million ($3 million for endowments and foundations), but the minimum may be waived if you have an aggregate investment in the American Century family of funds of $10 million or more ($5 million for endowments and foundations). This includes accounts held directly with American Century and those held through a financial intermediary.

There is no minimum initial investment amount for Y Class shares.

For the Investor, A and C Classes, there is no minimum initial investment amount for certain employer-sponsored retirement plans, however, financial intermediaries or plan recordkeepers may require plans to meet different minimums. Employer-sponsored retirement plans are not eligible to invest in the I or Y Class.

There is a $50 minimum for subsequent purchases, except that there is no subsequent purchase minimum for financial intermediaries or employer-sponsored retirement plans.

**Tax Information**

The fund intends to distribute income that is exempt from regular federal income tax, however, fund distributions may be subject to capital gains tax. A portion of the fund's distributions may be subject to federal income tax or to the federal alternative minimum tax.

If you hold your fund shares through a tax-deferred investment plan, such as a 401(k) plan or an IRA, any distributions received from the fund may be taxable as ordinary income upon withdrawal from the tax-deferred plan, regardless of whether the distributions were tax-exempt when earned.

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

If you purchase the fund through a broker-dealer or other financial intermediary (such as a bank, insurance company, plan sponsor or financial professional), the fund and its related companies may pay the intermediary for the sale of fund shares and related services for investments in all classes except the Y Class. 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.

<sup>©</sup>2025 American Century Proprietary Holdings, Inc. All rights reserved.

CL-SUM-91863 2510

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