Supplement to the currently effective  Statements of Additional  Information for
the below-listed funds.

Cash Management Fund Institutional
Cash Reserves Fund Institutional
Cash Reserve Fund, Inc.
         Prime Series
DWS Money Market Series

All references to securities  lending  practices in the Statements of Additional
Information  are hereby  revised to reflect the Board's  approval of  securities
lending  by the  Portfolio  (Fund)  in an  amount  equal to 33 1/3% of its total
assets.  Further,  the  following  additional  changes  are hereby  made to each
Statement of Additional Information.

The following  replaces  similar  language or  supplements  the  non-fundamental
investment restrictions of the Portfolio (Fund) relating to securities lending:

As a matter of  non-fundamental  policy, the Portfolio (Fund) currently does not
intend to lend  portfolio  securities  in an amount  greater than 33 1/3% of its
total assets.

The following  supplements  or replaces  related  disclosure in the  "Investment
Policies  and  Techniques"  section  of  the  fund's  Statements  of  Additional
Information:

Lending  of  Portfolio  Securities.   The  Portfolio  may  lend  its  investment
securities to approved institutional  borrowers who need to borrow securities in
order to complete certain  transactions,  such as covering short sales, avoiding
failures to deliver securities or completing  arbitrage  operations.  By lending
its investment securities, the Portfolio attempts to increase its net investment
income  through the  receipt of  interest  on the loan.  Any gain or loss in the
market  price of the  securities  loaned that might occur during the term of the
loan  would  belong to the  Portfolio.  The  Portfolio  may lend its  investment
securities  so long as the terms,  structure  and the  aggregate  amount of such
loans are not  inconsistent  with the 1940 Act or the rules and  regulations  or
interpretations  of the SEC  thereunder,  which currently  require,  among other
things, that (a) the borrower pledge and maintain with the Portfolio  collateral
consisting of liquid,  unencumbered  assets having a value at all times not less
than 100% of the value of the  securities  loaned,  (b) the borrower add to such
collateral whenever the price of the securities loaned rises (i.e., the borrower
"marks  to the  market"  on a daily  basis),  (c) the  loan be made  subject  to
termination  by the  Portfolio  at any  time,  and  (d) the  Portfolio  receives
reasonable  interest on the loan (which may include the Portfolio  investing any
cash collateral in interest bearing short-term  investments),  and distributions
on the loaned  securities  and any increase in their market value.  There may be
risks of delay in  recovery  of the  securities  or even  loss of  rights in the
collateral  should the borrower of the  securities  fail  financially.  However,
loans will be made only to borrowers selected by the Portfolio's  delegate after
a commercially reasonable review of relevant facts and circumstances,  including
the creditworthiness of the borrower.

The Portfolio may pay  negotiated  fees in  connection  with loaned  securities,
pursuant to written  contracts.  In  addition,  voting  rights may pass with the
loaned  securities,  but if a material  event occurs  affecting an investment on
loan, the loan must be called and the securities voted. Pursuant to an exemptive
order  granted by the SEC,  cash  collateral  received by the  Portfolio  may be
invested  in a  money  market  fund  managed  by  the  Advisor  (or  one  of its
affiliates).



               Please Retain This Supplement for Future Reference


August 13, 2008