In the US, CD insurance is provided by the Federal Deposit Insurance Corporation (FDIC) at banks and by the National Credit Union Administration (NCUA) at credit unions. These are the same organizations that insure savings accounts and checking accounts. Basic coverage is $250,000 per depositor per bank. A joint account would be insured for $500,000.
Financial institutions must meet the FDIC or NCUA guidelines to receive benefits. Some institutions use a private insurance company instead of federally backed insurance. If the customers at an institution have high enough balances, the institution may also implement supplemental insurance from private companies. Investors should always be conscious of the amount and source of insurance for their deposits.