<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED
FROM JUNE 30, 2000 SEMI-ANNUAL REPORT AND IS QUALIFIED
IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<SERIES>
<NUMBER> 3
<NAME> OBERWEIS MID-CAP PORTFOLIO
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-START> JAN-01-2000
<PERIOD-END> JUN-30-2000
<INVESTMENTS-AT-COST> 11,511
<INVESTMENTS-AT-VALUE> 16,374
<RECEIVABLES> 66
<ASSETS-OTHER> 22
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 16,462
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 151
<TOTAL-LIABILITIES> 151
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 6,102
<SHARES-COMMON-STOCK> 564
<SHARES-COMMON-PRIOR> 580
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 5,319
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 4,890
<NET-ASSETS> 16,311
<DIVIDEND-INCOME> 1
<INTEREST-INCOME> 1
<OTHER-INCOME> 0
<EXPENSES-NET> 141
<NET-INVESTMENT-INCOME> (139)
<REALIZED-GAINS-CURRENT> 4,023
<APPREC-INCREASE-CURRENT> (1,122)
<NET-CHANGE-FROM-OPS> 2,762
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> 0
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 173
<NUMBER-OF-SHARES-REDEEMED> (189)
<SHARES-REINVESTED> 0
<NET-CHANGE-IN-ASSETS> 2,226
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 0
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 31
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 147
<AVERAGE-NET-ASSETS> 15,746
<PER-SHARE-NAV-BEGIN> 24.29
<PER-SHARE-NII> (.25)
<PER-SHARE-GAIN-APPREC> 4.87
<PER-SHARE-DIVIDEND> 0
<PER-SHARE-DISTRIBUTIONS> 0
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 28.91
<EXPENSE-RATIO> 1.88
</TABLE>
