0000891092-14-006680.txt : 20140903 0000891092-14-006680.hdr.sgml : 20140903 20140903171507 ACCESSION NUMBER: 0000891092-14-006680 CONFORMED SUBMISSION TYPE: 497 PUBLIC DOCUMENT COUNT: 1 FILED AS OF DATE: 20140903 DATE AS OF CHANGE: 20140903 EFFECTIVENESS DATE: 20140903 FILER: COMPANY DATA: COMPANY CONFORMED NAME: BLACKROCK MUNICIPAL BOND FUND, INC. CENTRAL INDEX KEY: 0000225635 IRS NUMBER: 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: 141081232 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 0000225635 S000002334 BlackRock National Municipal Fund C000006118 Investor A C000006119 Investor B C000006120 Investor C1 C000006121 Institutional C000038033 Investor C C000100249 Service Shares C000100250 BlackRock Shares C000100251 Investor B1 Shares 497 1 e60326_497.htm FORM 497

BLACKROCK MUNICIPAL BOND FUND, INC.

BlackRock National Municipal Fund

(the “Fund”)

 

Supplement dated September 3, 2014

to the Fund’s Prospectus and Summary Prospectus, each dated October 28, 2013

 

 

Effective September 1, 2014, the following changes are made to the Fund’s Prospectus and Summary Prospectus:

The section of the Fund’s Prospectus entitled “Fund Overview — Key Facts About BlackRock National Municipal Fund — Performance Information” and the section of the Fund’s Summary Prospectus entitled “Key Facts About BlackRock National Municipal Fund — Performance Information” are supplemented as follows:

 

The Custom National Index is added as a performance benchmark against which the Fund measures its performance. The Custom National Index is a customized benchmark that reflects the returns of the S&P® Municipal Bond Index for periods prior to January 1, 2013, and the returns of only those bonds in the S&P® Municipal Bond Index that have maturities greater than 5 years for periods subsequent to January 1, 2013. Fund management believes that the addition of this performance benchmark more accurately reflects the investment strategy of the Fund. The Fund will continue to use the S&P® Municipal Bond Index as its primary performance benchmark.

 

For the one-, five- and ten-year periods ended December 31, 2012, the average annual total returns for the Custom National Index were 7.42%, 5.78% and 5.19%, respectively.

 

Shareholders should retain this Supplement for future reference.

 

ALLPR-MBFN-0914SUP