A sweep account is a bank or brokerage account feature that automatically moves, or sweeps, uninvested cash into a higher-yielding vehicle, such as a money market fund or interest-bearing account, at the end of each business day. The goal is to ensure your idle cash is always working for you rather than sitting in a low-interest account. When you need the funds for a transaction or investment, the money is automatically swept back into your main account. Sweep accounts are common in brokerage accounts, where uninvested cash might otherwise earn little to nothing while waiting to be deployed. They're a convenient, hands-off way to earn a modest return on cash you're not actively using.