WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000897513
<NAME> ACM MUNICIPAL SECURITIES INCOME FUND
<SERIES>
<NUMBER> 001
<NAME> ACM MUNICIPAL SECURITIES INCOME FUND
<S> <C>
<PERIOD-TYPE> YEAR
<FISCAL-YEAR-END> OCT-31-2000
<PERIOD-END> OCT-31-2000
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<INVESTMENTS-AT-VALUE> 213,189,119
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<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 447,866
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<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 237,618,348
<SHARES-COMMON-STOCK> 10,859,181
<SHARES-COMMON-PRIOR> 10,815,006
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (31,138,203)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 10,661,628
<NET-ASSETS> (21,674,187)
<DIVIDEND-INCOME> 0
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<OTHER-INCOME> 0
<EXPENSES-NET> 1,973,850
<NET-INVESTMENT-INCOME> 12,156,072
<REALIZED-GAINS-CURRENT> (9,889,773)
<APPREC-INCREASE-CURRENT> 11,654,720
<NET-CHANGE-FROM-OPS> 13,921,019
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (12,156,072)
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> (974,350)
<NUMBER-OF-SHARES-SOLD> 0
<NUMBER-OF-SHARES-REDEEMED> 0
<SHARES-REINVESTED> 501,540
<NET-CHANGE-IN-ASSETS> 1,292,137
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> (29,803,494)
<OVERDISTRIB-NII-PRIOR> (814,544)
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 1,062,794
<INTEREST-EXPENSE> 0
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<PER-SHARE-NAV-BEGIN> 11.64
<PER-SHARE-NII> 1.12
<PER-SHARE-GAIN-APPREC> 0.16
<PER-SHARE-DIVIDEND> (1.12)
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> (0.09)
<PER-SHARE-NAV-END> 11.71
<EXPENSE-RATIO> 0.93
[AVG-DEBT-OUTSTANDING] 0
[AVG-DEBT-PER-SHARE] 0.00
</TABLE>
