<PAGE>
Supplement to the North American Senior Floating Rate Fund
August 6, 1998 Prospectus
Effective February 1, 1999, the Fund's investment advisor, CypressTree Asset
Management Corporation, Inc. (CAM), has agreed to reimburse all but 0.15% of the
Other Expenses for the period 2/1/99 - 2/28/99, all but 0.30% of the Other
Expenses for the period 3/1/99 - 3/31/99 and all but 0.45% of the Other Expenses
for the period 4/1/99 - 4/30/99. These expenses will be phased in incrementally
throughout each month. After that date, unless reimbursement of some expenses is
further extended by CAM, the expense cap will revert to the one described on
page 3 of the Fund prospectus.
90416 January 29, 1999
PROSPECTUS DATED AUGUST 6, 1998