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               SUPPLEMENT TO THE CURRENTLY EFFECTIVE PROSPECTUSES:

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      Cash Management Fund Institutional     Cash Reserves Fund Institutional
         Institutional
                                             DWS Money Market Series
      Cash Reserve Fund                         Managed Shares
         Prime Series                           Institutional Shares

The following information supplements the disclosure in the "Other Policies and
Risks" section of each fund's prospectuses:

The fund may also post on the Web site, on a more frequent basis, a percentage
breakdown of the holdings of the fund by type of security.

The following information replaces similar disclosure in the "Policies You
Should Know About -- Transaction Processing" or "Policies You Should Know About
-- Policies about transactions" section of each fund's prospectuses or
supplements the disclosure in the "Policies You Should Know About -- Transaction
Processing" section of DWS Money Market Series -- Institutional Shares
prospectus:

Transaction Processing. Orders for the purchase of shares by wire transfer will
normally be effective at the share price next computed after receipt of the wire
transfer of the amount to be invested. If a wire transfer purchase order is
received in good form prior to 5:00 p.m. Eastern time, it will normally receive
the dividend for that day. Shareholders known to the fund may notify the fund's
transfer agent in advance of their wire transfer purchase by calling the fund's
transfer agent prior to the 5:00 p.m. Eastern time cut-off time and providing
the amount of the order. The shareholder will receive a confirmation number for
the trade. If the fund receives the wire transfer by the close of the Fed wire
system, the trade will be entitled to that day's dividend. If the fund does not
receive the wire transfer by the close of the Fed wire system, the trade may not
receive the dividend for that day and, depending upon the circumstances, the
trade may receive the dividend for the following business day or may be
cancelled or rejected and, in any case, the shareholder may be charged for any
losses or fees that result, which may be paid by deductions from their account
or otherwise. The fund's distributor may refuse to allow any shareholder to
trade with the



March 31, 2008
DMF-3660

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fund in this manner any require that the wire transfer of purchase proceeds be
received before the trade is considered in good form.

Investments by check will be effective on the business day following receipt and
will earn dividends the following business day.

Orders processed through dealers or other financial services firms via Fund/SERV
will be effected at the share price calculated on the trade day (normally the
date the order is received). Purchases processed via Fund/SERV will begin
earning dividends on the day a fund receives the payment (typically the next
business day). For redemptions processed via Fund/SERV, you generally will
receive dividends accrued up to, but not including, the business day that
payment for your shares are made.

When selling shares, shareholders generally receive dividends up to, but not
including, the business day following the day on which the shares were sold. If
the fund receives a sell request before 5:00 p.m. Eastern time and the request
calls for proceeds to be sent out by wire, the proceeds will normally be wired
on the same day. However, the shares sold will not earn that day's dividend.

As noted elsewhere in the prospectus, proceeds of a redemption may be delayed.
The ability to receive "same day" wire redemption proceeds can be affected by a
variety of circumstances including the time that the request is made, the level
of redemption requests and purchase orders and general market conditions.
Requests for same day wire that are received earlier in the day will be given
priority over requests received later in the day in the event that it is
necessary to limit the amount of same day wire redemptions.

The following information replaces similar disclosure under the "Policies You
Should Know About -- How the fund calculates share price" section of each fund's
prospectuses:

The fund is open for business each day the New York Stock Exchange is open.
Normally, the fund calculates its share price once every business day at 5:00
p.m. Eastern time. The close of regular trading on the Exchange is typically
4:00 p.m. Eastern time, but sometimes it is earlier, as in the case of scheduled
half-day trading or unscheduled suspensions of trading. In the event of
scheduled partial day trading or unscheduled suspensions of trading on the
Exchange, the calculation of share price shall be as of the close of trading on
the Exchange and the latest time for receipt of wire purchase transactions
entitled to receive same day dividend treatment and for receipt of redemption
orders for same day



March 31, 2008
DMF-3660


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wire transfer of proceeds will be the earlier of (a) the times set forth in the
prospectus or (b) the early closing time of the Exchange. The fund seeks to
maintain a stable $1.00 share price.

Except as provided below, purchase, redemption and exchange orders must be
received in good order by 4:00 p.m. Eastern time (or prior to the close of the
fund, if the Exchange closes early on such date) on a business day on which the
fund is open in order to be effective on that day; otherwise such orders will be
effective on the next business day. However, on a normal business day that the
fund calculates its share price at 5:00 p.m. Eastern time as provided above,
purchase orders with payment sent by wire and redemption orders with proceeds to
be sent by wire, ACH or check that are communicated by telephone (but not by the
Automated Information Line) and are received in good order by 5:00 p.m. Eastern
time on such business day will be effective on that business day.

The fund may, but is not required to, accept certain types of purchase and
redemption orders (not including exchanges) on days that the Exchange is closed,
or beyond an Exchange early closing time (referred to as a "Limited Trading
Period") if: (a) the Federal Reserve system is open, (b) the primary trading
markets for the fund's portfolio instruments are open and (c) the Advisor
believes there will be adequate liquidity in the short-term markets. During any
such Limited Trading Period, the fund will only accept purchase orders by wire
with advance telephone notification and telephone redemption orders with
proceeds to be sent by wire, ACH or check and will not accept orders by any
other means. (Automated Telephone Line orders are not permitted.) If redemption
proceeds are requested by ACH or check, the transmission of the ACH payment or
the mailing of the check, as the case may be, will be delayed by at least one
business day in comparison to normal trading periods. Orders submitted by other
means will be processed on the next day that the Exchange is open. The
calculation of share price will be at the time set forth in the prospectus for
normal trading days. Orders must be submitted by the cut-off times for receipt
of wire purchases entitled to that day's dividend and for receipt of telephone
redemption orders for same day wire transfer, which will be the earlier of: (a)
the times set forth in the prospectus for normal trading days or (b) such
earlier times that the fund determines based on the criteria described above. If
redemption proceeds are requested by ACH or check, orders must be received prior
to the calculation of share price. Please call (877) 237-1131 or visit our Web
site at www.moneyfunds.deam-us.db.com for additional

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information about whether the fund will be open for business on a particular
day. Information concerning the intention of a fund to be open for a Limited
Trading Period will be available at least one business day prior to the
applicable day that the Exchange is closed or is closing early in the case of
scheduled closings and as soon as practical in the case of unscheduled closings.















               Please Retain This Supplement for Future Reference



March 31, 2008
DMF-3660


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