# EDGAR Filing Document

**Accession Number:** 0000798737
**File Stem:** 0001193125-25-220347
**Filing Date:** 2025-9
**Character Count:** 25430
**Document Hash:** 5ffcd7cd6d7f94e92c6e784591914599
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-220347.hdr.sgml**: 20250926

**ACCESSION NUMBER**: 0001193125-25-220347

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 4

**FILED AS OF DATE**: 20250926

**DATE AS OF CHANGE**: 20250926

**EFFECTIVENESS DATE**: 20250926

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** AB MUNICIPAL INCOME FUND, INC.
- **CENTRAL INDEX KEY:** 0000798737

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** MA
- **FISCAL YEAR END:** 1031

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 033-07812
- **FILM NUMBER:** 251349902

**BUSINESS ADDRESS:**
- **STREET 1:** ALLIANCEBERNSTEIN LP
- **STREET 2:** 66 HUDSON BOULEVARD EAST, 26TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10001
- **BUSINESS PHONE:** 2129691000

**MAIL ADDRESS:**
- **STREET 1:** ALLIANCEBERNSTEIN LP
- **STREET 2:** 66 HUDSON BOULEVARD EAST, 26TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10001

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ALLIANCEBERNSTEIN MUNICIPAL INCOME FUND INC
- **DATE OF NAME CHANGE:** 20030319

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ALLIANCE MUNICIPAL INCOME FUND INC/NY/
- **DATE OF NAME CHANGE:** 20010629

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ALLIANCE MUNICIPAL INCOME FUND INC/NY
- **DATE OF NAME CHANGE:** 20010629

## Series and Classes Contracts Data

### AB High Income Municipal Portfolio (Series ID: S000027380)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000082627 | Class A       | ABTHX           |
| C000082628 | Class C       | ABTFX           |
| C000082629 | Advisor Class | ABTYX           |
| C000206561 | Class Z       | ABTZX           |

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| | |
|:---|:---|
| ![LOGO](g947693g67z55.jpg) | SUMMARY PROSPECTUS September 30, 2025 |

---

## AB High Income Municipal Portfolio
**Ticker:** Class A–ABTHX; Class C–ABTFX; Advisor Class–ABTYX; Class Z–ABTZX

Before you invest, you may want to review the Portfolio's Prospectus, which contains more information about the Portfolio and its risks. The Portfolio's Prospectus and Statement of Additional Information ("SAI"), both dated September 30, 2025, as may be amended or supplemented, are incorporated by reference into this Summary Prospectus. For free paper or electronic copies of the Portfolio's Prospectus, reports to shareholders and other information about the Portfolio, go to <u>www.abfunds.com/go/prospectus</u>, email a request to prorequest@alliancebernstein.com, call (800) 227-4618, or ask any financial advisor, bank, or broker-dealer who offers shares of the Portfolio.

**PRO-0116-HIM-0925** 

**INVESTMENT OBJECTIVE:** 

The investment objective of the Portfolio is to earn the highest level of current income, exempt from federal income tax, that is available consistent with what the Adviser considers to be an appropriate level of risk.

**FEES AND EXPENSES OF THE PORTFOLIO:** 

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Portfolio. **You may be required to pay commissions and/or other forms of compensation to a broker for transactions in Advisor Class shares, which are not reflected in the tables or the examples below.** You may qualify for sales charge reductions if you and members of your family invest, or agree to invest in the future, at least $100,000 in AB Mutual Funds. More information about these and other discounts is available from your financial intermediary and in Investing in the Portfolios—Sales Charge Reduction Programs for Class A Shares on page 47 of the Portfolio's Prospectus, in Appendix B—Financial Intermediary Waivers of the Portfolio's Prospectus and in Purchase of Shares—Sales Charge Reduction Programs for Class A Shares on page 124 of the Portfolio's SAI.

**Shareholder Fees** (fees paid directly from your investment)

---

| | | | | |
|:---|:---|:---|:---|:---|
| | **Class A**<br> **Shares** | **Class C**<br> **Shares** | **Advisor Class**<br> **Shares** | **Class Z**<br> **Shares** |
|  Maximum Sales Charge (Load) Imposed on Purchases<br> (as a percentage of offering price) | 3.00% |  |  |  |
|  Maximum Deferred Sales Charge (Load)<br> (as a percentage of offering price or redemption proceeds, whichever is lower) |  | 1.00%(a) |  |  |
|  Exchange Fee |  |  |  |  |

---

**Annual Portfolio Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment)

---

| | | | | |
|:---|:---|:---|:---|:---|
| | **Class A** | **Class C** | **Advisor Class** | **Class Z** |
|  Management Fees | .49% | .49% | .49% | .49% |
|  Distribution and/or Service (12b-1) Fees | .25% | 1.00% |  |  |
|  Other Expenses: |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp; Transfer Agent | .02% | .02% | .02% | .02% |
| &nbsp;&nbsp;&nbsp;&nbsp; Interest Expense | .33% | .33% | .33% | .33% |
| &nbsp;&nbsp;&nbsp;&nbsp; Other Expenses(b) | .03% | .03% | .03% | .03% |
|  Total Other Expenses | .38% | .38% | .38% | .38% |
|  Total Annual Portfolio Operating Expenses(c) | 1.12% | 1.87% | .87% | .87% |

---

(a) For Class C shares, the contingent deferred sales charge, or CDSC, is 0% after the first year. Class C shares
automatically convert to Class A shares after eight years.

(b) "Other Expenses" includes acquired fund fees and expenses totaling less than .01%.

------

(c) If interest expense were excluded, Total Annual Portfolio Operating Expenses would be as follows:

---

| | | | |
|:---|:---|:---|:---|
| **Class A** | **Class C** | **Advisor Class** | **Class Z** |
| .79% | 1.54% | .54% | .54% |

---

**Examples** 

The Examples are intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds. The Examples assume that you invest $10,000 in the Portfolio for the time periods indicated and then redeem all of your shares at the end of these periods. The Examples also assume that your investment has a 5% return each year, that the Portfolio's operating expenses stay the same and that any fee waiver and/or expense limitation remains in effect for only the first year. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

---

| | | | | |
|:---|:---|:---|:---|:---|
| | **Class A** | **Class C** | **Advisor Class** | **Class Z** |
|  After 1 Year | $411 | $290 \* | $89 | $89 |
|  After 3 Years | $645 | $588 | $278 | $278 |
|  After 5 Years | $898 | $1011 | $482 | $482 |
|  After 10 Years | $1622 | $1995 | $1073 | $1073 |

---

\* If you did not redeem your shares at the end of the period, your expenses would be decreased by approximately $100. 

**Portfolio Turnover** 

The Portfolio pays transaction costs, such as commissions, when it buys or sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Portfolio shares are held in a taxable account. These transaction costs, which are not reflected in the Annual Portfolio Operating Expenses or in the Examples, affect the Portfolio's performance. During the most recent fiscal year, the Portfolio's portfolio turnover rate was 24% of the average value of its portfolio.

**PRINCIPAL STRATEGIES:** 

The Portfolio pursues its objective by investing principally in high-yielding municipal securities that may be non-investment grade or investment grade. As a matter of fundamental policy, the Portfolio invests, under normal circumstances, at least 80% of its net assets in municipal securities that pay interest that is exempt from federal income tax. These securities may pay interest that is subject to the federal alternative minimum tax for certain taxpayers.

The Adviser selects securities for purchase or sale based on its assessment of the securities' risk and return characteristics as well as the securities' impact on the overall risk and return characteristics of the Portfolio. In making this assessment, the Adviser takes into account various factors including the credit quality and sensitivity to interest rates of the securities under consideration and of the Portfolio's other holdings.

The Portfolio may invest without limit in lower-rated securities ("junk bonds"), which may include securities having the lowest rating, and in unrated securities that, in the Adviser's judgment, would be lower-rated securities if rated. The Portfolio may invest in fixed-income securities with any maturity or duration. The Portfolio will seek to increase income for shareholders by investing in longer-maturity bonds. Consistent with its objective of seeking a higher level of income, the Portfolio may experience greater volatility and a higher risk of loss of principal than other municipal funds.

The Portfolio may also invest in:

• forward commitments;

• tender option bonds;

• zero-coupon municipal securities and variable, floating and inverse floating-rate municipal securities;

• certain types of mortgage-related securities; and

• derivatives, such as options, futures contracts, forwards and swaps.

The Portfolio may make short sales of securities or maintain a short position, and may use other investment techniques.

**PRINCIPAL RISKS:** 

• **Market Risk:** The value of the Portfolio's assets will fluctuate as the market or markets in which
the Portfolio invests fluctuate. The value of the Portfolio's investments may decline, sometimes rapidly and unpredictably, simply because of economic changes or other events, including public health crises (including the occurrence of a
contagious disease or illness), terrorism, war, changing interest rate levels, imposition of new or additional tariffs, and regional and global conflicts, that affect large portions of the market.

------

• **Interest Rate Risk:** Changes in interest rates will affect the value of investments in fixed-income
securities. When interest rates rise, the value of existing investments in fixed-income securities tends to fall and this decrease in value may not be offset by higher income from new investments. Interest rate risk is generally greater for
fixed-income securities with longer maturities or durations. Changing interest rates may have unpredictable effects on the markets, may result in heightened market volatility and may detract from Portfolio performance. In addition, changes in
monetary policy may exacerbate the risks associated with changing interest rates.

• **Duration Risk:** Duration is a measure that relates the expected price volatility of a fixed-income security
to changes in interest rates. The duration of a fixed-income security may be shorter than or equal to the full maturity of a fixed-income security. Fixed-income securities with longer durations have more risk and will decrease in price as interest
rates rise.

• **Below Investment Grade Securities Risk:** Investments in fixed-income securities with lower ratings
(commonly known as "junk bonds") have a higher probability that an issuer will default or fail to meet its payment obligations. These securities may be subject to greater price volatility due to such factors as specific corporate
developments, interest rate sensitivity and negative performance of the junk bond market generally and may be more difficult to trade than other types of securities.

• **Municipal Market Risk:** This is the risk that special factors may adversely affect the value of municipal
securities and have a significant effect on the yield or value of the Portfolio's investments in municipal securities. These factors include economic conditions, political or legislative changes, public health crises, uncertainties related to
the tax status of municipal securities, and the rights of investors in these securities. To the extent that the Portfolio invests more of its assets in the municipal securities of a particular state or territory, the Portfolio may be vulnerable to
events adversely affecting that state or territory, including economic, political and regulatory occurrences, court decisions, terrorism, public health crises (including the occurrence of a contagious disease or illness) and catastrophic natural
disasters, such as hurricanes, fires or earthquakes. The Portfolio's investments in certain municipal securities with principal and interest payments that are made from the revenues of a specific project or facility, and not general tax
revenues, may have increased risks. Factors affecting the project or facility, such as local business or economic conditions, could have a significant effect on the project's ability to make payments of principal and interest on these
securities.

In addition, changes in tax rates or the treatment of income from certain types of municipal securities, among other things, could negatively affect the municipal securities markets.

The municipal securities issued by Puerto Rico and its government agencies and municipalities may have more risks than those of other U.S. issuers of municipal securities. Puerto Rico continues to face a challenging economic and fiscal environment. If the general economic situation in Puerto Rico persists or worsens, the volatility and credit quality of Puerto Rican municipal securities could continue to be adversely affected, and the market for such securities may deteriorate further.

• **Inflation Risk:** This is the risk that the value of assets or income from investments will be less in the
future as inflation decreases the value of money. As inflation increases, the value of the Portfolio's assets can decline as can the value of the Portfolio's distributions. This risk is significantly greater for fixed-income securities
with longer maturities.

• **Credit Risk:** An issuer or guarantor of a fixed-income security, or the counterparty to a derivatives or
other contract, may be unable or unwilling to make timely payments of interest or principal, or to otherwise honor its obligations. The issuer or guarantor may default, causing a loss of the full principal amount of a security and accrued interest.
The degree of risk for a particular security may be reflected in its credit rating. There is the possibility that the credit rating of a fixed-income security may be downgraded after purchase, which may adversely affect the value of the security.

• **Leverage Risk:** To the extent the Portfolio uses leveraging techniques, such as TOBs, its net asset value
("NAV") may be more volatile because leverage tends to exaggerate the effect of changes in interest rates and any increase or decrease in the value of the Portfolio's investments.

• **Tax Risk:** There is no guarantee that the income on the Portfolio's municipal securities will be
exempt from regular U.S. federal, and if applicable, state income taxes. From time to time, the U.S. Government and the U.S. Congress consider changes in U.S. federal income tax law that could limit or eliminate the federal tax exemption for
municipal bond income, which would in effect reduce the income received by shareholders from the Portfolio by increasing taxes on that income. In such event, the Portfolio's NAV could also decline as yields on municipal bonds, which are
typically lower than those on taxable bonds, would be expected to increase to approximately the yield of comparable taxable bonds. Actions or anticipated actions affecting the tax exempt status of municipal bonds could also result in significant
shareholder redemptions of Portfolio shares as investors anticipate adverse effects on the Portfolio or seek higher yields to offset the potential loss of the tax deduction. As a result, the Portfolio would be required to maintain higher levels of
cash to meet the redemptions, which would negatively affect the Portfolio's yield.

• **Illiquid Investments Risk:** Illiquid investments risk exists when certain investments are or become
difficult to purchase or sell. Difficulty in selling such investments may result in sales at disadvantageous prices affecting the value of your investment in the

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Portfolio. Causes of illiquid investments risk may include low trading volumes, large positions and heavy redemptions of Portfolio shares. Illiquid investments risk may be higher in a rising interest rate environment, when the value and liquidity of fixed-income securities generally decline. Municipal securities may have more illiquid investments risk than other fixed-income securities because they trade less frequently and the market for municipal securities is generally smaller than many other markets. <br>

• **Derivatives Risk:** Derivatives may be difficult to price or unwind and leveraged so that small changes may
produce disproportionate losses for the Portfolio. A short position in a derivative instrument involves the risk of a theoretically unlimited increase in the value of the underlying asset, reference rate or index, which could cause the Portfolio to
suffer a potentially unlimited loss. Derivatives, especially over-the-counter derivatives, are also subject to counterparty risk, which is the risk that the counterparty (the party on the other side of the transaction) on a derivative transaction
will be unable or unwilling to honor its contractual obligations to the Portfolio.

• **Tender Option Bonds Risk:** The Portfolio's participation in TOB transactions may reduce the
Portfolio's returns and increase volatility and expose the Portfolio to credit risk and leverage risk. Investments in TOB transactions typically will involve greater risk than investments in fixed rate municipal bonds, including the risk
of loss of principal. The interest payments that the Portfolio receives in connection with a TOB transaction ("inverse floaters") vary inversely with short-term interest rates and will be reduced, or potentially eliminated, when
short-term interest rates rise. The Portfolio will be subject to leverage risk to the extent that the Portfolio uses the proceeds from a TOB transaction to invest in other securities. If the interest expense on borrowings or other costs of the
leverage approach the net return on the Portfolio's investment portfolio or investments made through leverage, as applicable, the benefit of leverage to the Portfolio's shareholders will be reduced. If the interest expense on borrowings
or other costs of leverage were to exceed the net return to the Portfolio, the Portfolio's use of leverage would result in a lower rate of net return than if the Portfolio were not leveraged. During periods of rising short-term interest rates,
the interest paid on floaters in TOBs would increase, which may adversely affect the Portfolio's net return. The Portfolio's investment in a TOB will generally underperform the market for fixed rate municipal securities when interest
rates rise. The value of inverse floaters may be volatile and there may be limited liquidity in the market for inverse floaters. Because investments in inverse floaters issued in TOB transactions are derivative instruments, these investments are
also subject to the risks associated with investments in derivatives.

• **Management Risk:** The Portfolio is subject to management risk because it is an actively-managed investment
fund. The Adviser will apply its investment techniques and risk analyses in making investment decisions, but there is no guarantee that its techniques will produce the intended results. Some of these techniques may incorporate, or rely upon,
quantitative models, but there is no guarantee that these models will generate accurate forecasts, reduce risk or otherwise perform as expected.

As with all investments, you may lose money by investing in the Portfolio.

**BAR CHART AND PERFORMANCE INFORMATION:** 

The bar chart and performance information provide an indication of the historical risk of an investment in the Portfolio by showing:

• how the Portfolio's performance changed from year to year over ten years; and

• how the Portfolio's average annual returns for one, five and ten years compare to those of a broad-based
securities market index.

You may obtain updated performance information on the Portfolio's website at <u>www.abfunds.com</u> (click on "Investments—Mutual Funds").

The Portfolio's past performance before and after taxes, of course, does not necessarily indicate how it will perform in the future.

**Bar Chart** 

The annual returns in the bar chart are for the Portfolio's Class A shares and do not reflect sales loads. If sales loads were reflected, returns would be less than those shown. Through June 30, 2025, the year-to-date unannualized return for Class A shares was -1.10%.

![LOGO](g947693g01a18.jpg)

During the period shown in the bar chart, the Portfolio's:

**Best Quarter was up 10.15%, 4th quarter, 2023; and Worst Quarter was down -7.60%, 1st quarter, 2022.** 

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**Performance Table** 

**Average Annual Total Returns** 

(For the periods ended December 31, 2024)

---

| | | | | |
|:---|:---|:---|:---|:---|
| | | **1 Year** | **5 Years** | **10 Years** |
| Class A\* | Return Before Taxes | 1.21% | 0.30% | 2.72% |
|  | Return After Taxes on Distributions | 1.13% | 0.20% | 2.63% |
|  | Return After Taxes on Distributions and Sale of Portfolio Shares | 2.21% | 0.96% | 2.90% |
| Class C | Return Before Taxes | 2.58% | 0.14% | 2.27% |
| Advisor Class | Return Before Taxes | 4.62% | 1.15% | 3.29% |
| Class Z\*\* | Return Before Taxes | 4.62% | 1.16% | 3.30% |
| Bloomberg Municipal Bond Index<br> (reflects no deduction for fees, expenses or taxes) | Bloomberg Municipal Bond Index<br> (reflects no deduction for fees, expenses or taxes) | 1.05% | 0.99% | 2.25% |

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\* After-tax Returns:

– Are shown for Class A shares only and will vary for the other Classes of shares because these Classes have different expense ratios;

– Are an estimate, which is based on the highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes; actual after-tax returns depend on an individual investor's tax situation and are likely to differ from those shown; and

– Are not relevant to investors who hold Portfolio shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.

\*\* Inception date for Class Z shares: 9/28/2018. Performance information for periods prior to the inception of Class Z shares is the performance of the Portfolio's Class A shares adjusted to reflect the expenses of Class Z shares.

**INVESTMENT ADVISER:** 

AllianceBernstein L.P. is the investment adviser for the Portfolio.

**PORTFOLIO MANAGERS:** 

The following table lists the persons responsible for day-to-day management of the Portfolio's portfolio:

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| | | |
|:---|:---|:---|
| **Employee** | **Length of Service** | **Title** |
| Daryl Clements | Since 2022 | Senior Vice President of the Adviser |
| Matthew J. Norton | Since 2016 | Senior Vice President of the Adviser |
| Andrew D. Potter | Since 2018 | Senior Vice President of the Adviser |

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**PURCHASE AND SALE OF PORTFOLIO SHARES** 

**Purchase Minimums** 

The following table describes the initial and subsequent minimum purchase amounts for each class of shares, which are subject to waiver in certain circumstances.

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| | | |
|:---|:---|:---|
| | **Initial** | **Subsequent** |
| Class A/Class C shares, including traditional IRAs and Roth IRAs | $2500 | $50 |
| Automatic Investment Program |  | $50<br>If initial investment is<br>less than $2,500, then $200<br>monthly until account balance<br>reaches $2,500 |
| Advisor Class shares (only available to fee-based programs or through other limited arrangements and certain commission-based brokerage arrangements) |  |  |
| Class A and Class Z shares are available at NAV, without an initial sales charge, to 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit-sharing and money purchase pension plans, defined benefit plans, and non-qualified deferred compensation plans and, for Class Z shares, to persons participating in certain fee-based programs sponsored by a financial intermediary, where in each case plan level or omnibus accounts are held on the books of the Portfolio. |  |  |

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You may sell (redeem) your shares each day the New York Stock Exchange is open. You may sell your shares through your financial intermediary or by mail (AllianceBernstein Investor Services, Inc., P.O. Box 786003, San Antonio, TX 78278-6003) or telephone ((800) 221-5672).

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**TAX INFORMATION** 

The Portfolio may make capital gains distributions, which may be taxable as ordinary income or capital gains, and income dividends. The Portfolio anticipates that substantially all of its income dividends will be exempt from regular federal income tax.

**PAYMENTS TO BROKER-DEALERS AND OTHER FINANCIAL INTERMEDIARIES** 

If you purchase shares of 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 Portfolio shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other financial intermediary and your salesperson to recommend the Portfolio over another investment. Ask your salesperson or visit your financial intermediary's website for more information.

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| | |
|:---|:---|
| **PRO-0116-HIM-0925** | ![LOGO](g947693g22c48.jpg) |

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