<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
This schedule contains summary financial information
extracted from Merrimac Series,
form N-SAR for the period ended June 30, 2000
and is qualified in its entirety by reference to
such financial statements.
</LEGEND>
<SERIES>
<NUMBER> 015
<NAME> Merrimac U.S. Government Series Institutio
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-END> JUN-30-2000
<INVESTMENTS-AT-COST> 143,399,864
<INVESTMENTS-AT-VALUE> 143,399,864
<RECEIVABLES> 0
<ASSETS-OTHER> 7,004
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 143,406,868
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 863,398
<TOTAL-LIABILITIES> 863,398
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 142,548,336
<SHARES-COMMON-STOCK> 142,498,319
<SHARES-COMMON-PRIOR> 0
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> (4,864)
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 0
<NET-ASSETS> 142,493,455
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 4,499,866
<OTHER-INCOME> 0
<EXPENSES-NET> 382,267
<NET-INVESTMENT-INCOME> 4,117,599
<REALIZED-GAINS-CURRENT> (5,871)
<APPREC-INCREASE-CURRENT> 0
<NET-CHANGE-FROM-OPS> 4,111,728
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 4,117,599
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 465,581,167
<NUMBER-OF-SHARES-REDEEMED> 453,768,577
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 11,812,590
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 0
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 382,288
<AVERAGE-NET-ASSETS> 149,679,684
<PER-SHARE-NAV-BEGIN> 1.00
<PER-SHARE-NII> 0.03
<PER-SHARE-GAIN-APPREC> 0.00
<PER-SHARE-DIVIDEND> (0.03)
<PER-SHARE-DISTRIBUTIONS> 0.00
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 1.00
<EXPENSE-RATIO> 0.51
</TABLE>