<DOCUMENT>
<TYPE>497
<SEQUENCE>1
<FILENAME>c33498e497.txt
<DESCRIPTION>DEFINITIVE MATERIAL
<TEXT>
<PAGE>
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                                                  (RIVERSOURCE INVESTMENTS LOGO)

                   PROSPECTUS SUPPLEMENT DATED JULY 31, 2008*

<Table>
<Caption>
FUND                                                                  PROSPECTUS DATE     FORM #
<S>                                                                   <C>              <C>
RiverSource Floating Rate Fund                                         Sept. 28, 2007  S-6501-99 D
RiverSource Income Builder Basic Income Fund                           March 31, 2008  S-6394-99 E
RiverSource Income Builder Enhanced Income Fund                        March 31, 2008  S-6394-99 E
RiverSource Income Builder Moderate Income Fund                        March 31, 2008  S-6394-99 E
RiverSource Strategic Income Allocation Fund                            Nov. 29, 2007  S-6287-99 C
</Table>


The "Portfolio Manager(s)" section under "Fund Management and
Compensation -- Investment Manager" section is revised:

Effective immediately, Erol Sonderegger no longer serves as portfolio manager to
the Fund.


--------------------------------------------------------------------------------
S-6394-3 A (7/08)
* Valid until next prospectus update.

<PAGE>

S-6394-3 A (7/08)

</TEXT>
</DOCUMENT>