A certificate of deposit (or CD) is a savings instrument offered by a bank or credit union that has a fixed date of maturity and a fixed interest rate. A credit union might use the term Share Certificate, Term Certificate or just Certificate to refer to the same product. Most CDs require a minimum deposit amount and may offer rates contingent on the size of the deposit. As a CD depositor, you are committing to leave your funds in the CD for the term of the CD. As a result of that time commitment, rates offered on CDs are typically higher than traditional savings or money market accounts. Keep in mind that an early withdrawal of funds will likely come with a financial penalty.