X0101 EFFECT 33 LIVE 2006-07-12 0000891092-06-001881 485APOS 0000225635 MERRILL LYNCH MUNICIPAL BOND FUND INC 002-57354 S000011867 High Yield Portfolio C000032425 Class A S000011867 High Yield Portfolio C000032426 Class B S000011867 High Yield Portfolio C000032427 Class C S000011867 High Yield Portfolio C000032428 Class I