# EDGAR Filing Document

**Accession Number:** 0000225635
**File Stem:** 0001193125-25-140734
**Filing Date:** 2025-6
**Character Count:** 3335
**Document Hash:** 9481216348dfb86fe58f9d100b6e8b89
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-140734.hdr.sgml**: 20250613

**ACCESSION NUMBER**: 0001193125-25-140734

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20250613

**DATE AS OF CHANGE**: 20250613

**EFFECTIVENESS DATE**: 20250613

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** BLACKROCK MUNICIPAL BOND FUND, INC.
- **CENTRAL INDEX KEY:** 0000225635

**ORGANIZATION NAME:**
- **EIN:** 132896246
- **STATE OF INCORPORATION:** NJ
- **FISCAL YEAR END:** 0630

**FILING VALUES:**
- **FORM TYPE:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 002-57354
- **FILM NUMBER:** 251046538

**BUSINESS ADDRESS:**
- **STREET 1:** 100 BELLEVUE PARKWAY
- **CITY:** WILMINGTON
- **STATE:** DE
- **ZIP:** 19809
- **BUSINESS PHONE:** 800-441-7762

**MAIL ADDRESS:**
- **STREET 1:** 100 BELLEVUE PARKWAY
- **CITY:** WILMINGTON
- **STATE:** DE
- **ZIP:** 19809

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MERRILL LYNCH MUNICIPAL BOND FUND INC
- **DATE OF NAME CHANGE:** 19920703

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ONE LIBERTY MUNICIPAL BOND FUND INC
- **DATE OF NAME CHANGE:** 19780622

## Series and Classes Contracts Data

### BlackRock Impact Municipal Fund (Series ID: S000075512)

---

|  |  |
|:---|:---|
| Class Name    | Class ID   |
| Investor A    | C000234660 |
| Institutional | C000234661 |
| Class K       | C000234662 |

---

## Series and Classes Contracts Data

### BlackRock Impact Municipal Fund (Series ID: S000075512)

| Class ID   | Class Name    | Ticker Symbol   |
|:---|:---|:---|
| C000234660 | Investor A    |  |
| C000234661 | Institutional |  |
| C000234662 | Class K       |  |

**BLACKROCK MUNICIPAL BOND FUND, INC.** 

BlackRock Impact Municipal Fund

**Supplement dated June 13, 2025 (the "Supplement")** 

**to the Fund's Summary Prospectuses, Prospectuses and Statement of Additional Information,** 

**each dated September 27, 2024, as supplemented to date** 

On June 5, 2025, the Board of Directors of BlackRock Municipal Bond Fund, Inc. (the "Corporation"), on behalf of its series, BlackRock Impact Municipal Fund (the "Fund"), approved a proposal to close the Fund to new and subsequent investments and thereafter to liquidate the Fund. Accordingly, effective 4:00 P.M. (Eastern time) on September 12, 2025, the Fund will no longer accept orders from new investors or existing shareholders to purchase Fund shares. On or about September 19, 2025 (the "Liquidation Date"), all of the assets of the Fund will have been liquidated completely, the shares of any shareholders holding shares on the Liquidation Date will be redeemed at the net asset value per share and the Fund will then be terminated as a series of the Corporation.

Shareholders may redeem their Fund shares or exchange their shares into shares of another mutual fund advised by BlackRock Advisors, LLC or its affiliates at any time prior to the Liquidation Date. In preparation for the liquidation, the Fund may deviate from its investment objective and principal investment strategies.

Shareholders should consult their personal tax advisers concerning their tax situation and the impact of the liquidation and/or exchanging to a different fund on their tax situation.

**Shareholders should retain this Supplement for future reference.** 

PR2SAI-IMPF-0525SUP