Definition of sweep account

transaction account that offers convertibility of balances above some minimum into a higher-yielding savings or investment instrument, such as a money market mutual fund or overnight repurchase agreement. Balances above the specified amount periodically are transferred into a money market mutual fund or repurchase agreement. A variation is the repurchase agreement, or sweep repo, in which funds are moved from a depositor's account and invested in government securities. The next banking day, the customer's funds, plus interest, are recredited to the deposit account.

bank or other depository account that provides for automatic overnight investment of all or a portion of idle balances.