A minimum deposit is the smallest amount of money that an investor can use to open an account. Minimum deposits are frequently required for credit union savings accounts and for brokerage accounts. Minimum deposits putatively defray the expenses incurred by the financial institution when opening a new account. Most credit unions require a minimum deposit (which subsequently cannot be withdrawn unless the account is closed) of something in the neighborhood of $25, while most brokerages would require something more like $500 to $2,000. Term savings accounts such as certificates of deposit (CDs) usually require a minimum deposit of about $500 or more.