Potential disadvantages include limited transactions, fees, withdrawal restrictions, and minimum balance requirements. Banks and credit unions generally require customers to deposit a certain amount of money to open an account and to keep their account balance above a certain level. Many will impose monthly fees if the balance falls below the minimum. While some MMAs offer attractive rates, most will not be able to compete with other higher-yielding alternatives. Banks and credit unions offer many types of accounts, some with features that can make them competitive with—or superior to—money market accounts. Although the Federal Reserve amended withdrawal restrictions, banks may limit the amount of times that depositors can take money out of their MMAs.