Certificate of deposit

A certificate of deposit (CD) is a debt instrument issued by a bank or a credit union. A CD earns its stated interest for the stated term and pays interest at a stated frequency (monthly, quarterly, or annually). CDs at credit unions are sometimes called money market certificates. Unlike a money market fund, there is no credit risk with a money market certificate as long as you stay within the deposit insurance guarantee.

Please see CDs vs bonds as well.

Role in a portfolio

 * General savings vehicle. If you know the date on which you need a large amount of cash (car, college tuition, vacation, etc), you might consider opening a CD such that it will mature just before the date.
 * A part of fixed income allocation in a retirement portfolio. CDs are simply bonds with special characteristics (see CDs vs bonds). A common method of holding CDs in a portfolio is  laddering.

Credit risk
When purchased correctly, CDs do not have credit risk. Only bank accounts and treasury bonds share this enormously valuable feature of a government guarantee.

CDs from qualified banks are insured by Federal Deposit Insurance Corporation (FDIC). CDs from qualified credit unions are insured by National Credit Union Administration (NCUA). You can make sure the institution you are buying from is covered by FDIC or NCUA by checking their status:
 * FDIC: Bank Find
 * NCUA: ​Share Insurance Toolkit

The standard insurance amount is $250,000 per depositor, per insured bank, for each account ownership category.

Thus, if you want to safely invest more than $250,000 at the same institution, you can do so using payable-on-death (POD) labeling. For example, a couple with two children can insure $2.5 M. (They would hold a joint CD with $500 K; an individual CD each; 3 CDs for her POD for each of him, child 1 and child 2; and 3 CDs for him POD each of her, child 1 and child 2). Details are at the Bankdeals blog and the FDIC. The FDIC Insurance Electronic Deposit Insurance Estimator (EDIE) can help make sure you do this right.

Banks fail regularly and so it is critical to take these rules seriously. Do not ever buy CDs greater than the insurance guarantee or at a non-guaranteed institution. In particular, there are a small number of credit unions that are not insured by the NCUA. Even if these credit unions offered slightly higher rates on their CDs (and they generally don't), it would not be worth forgoing the government guarantee. If you have large amounts of money to invest in CDs, you should investigate the private CDARS service, which automatically distributes your money (up to $50 M) across a large number of institutions.

Inflation risk
CDs are effectively nominal bonds and are exposed to inflation risk. The bank promises that you will receive the stated interest payments for the life of the CD, plus be paid back the principal at maturity, but there is no guarantee that the future dollars will be worth as much as present dollars. (Also, in the case of bank failure, the FDIC only guarantees return of your principal and accumulated interest; sometimes the new bank that takes over the CD cuts the interest rate). Inflation risk can be partially mitigated by redemption of a CD prior to its maturity date. Early redemption invokes a penalty as a reduction in the amount of accrued interest. Based on market conditions, such as higher interest rates, it may be beneficial to redeem an existing CD early (known as "breaking" the CD) in order to pursue a more attractive alternative. (See Comparing CDs)).

Early withdrawal penalty
If you need money in your CD before it matures, or wish to redeem the CD early to reinvest at higher rates, you may be subject to early withdrawal penalty. According to a survey conducted by Bankrate.com, early withdrawal penalties vary widely. The most common penalties are 3 months and 6 months interest.

Usually the full interest payment from a CD is reported as taxable income. The early withdrawal penalty is deductible as an adjustment to income on a federal income tax return. The early withdrawal penalty will be shown in box 2 of the 1099-INT form (see Figure 1.)

Taxation
If held in a taxable account, interest from CDs is taxed as ordinary income for federal income tax. Unlike money market funds, there are no tax-exempt CDs. Taxation at the state level vary. Some states, including Massachusetts, may exempt interest from in-state banks.

Where to Buy?
When purchasing CDs, there is a trade-off between convenience and yield. The following is a list of options.

Your local bank or credit union
When saving money for a specific future cash need, it can be simplest to purchase a CD with money from your checking account. These rates are always better than checking account interest, but often are not very good. Also, beware of "teaser" rates that automatically roll-over into much lower yielding CDs when they mature. You often have just 10 days or so to stop a roll-over, so be sure to mark your calendar.

Out of town banks or credit unions
Different banks and credit unions around the country are constantly offering special deals to attract new customers. If you're willing to fill out the paperwork to move your money, you can get the highest yield CDs by moving your money to whatever bank is offering the best deal as your old CD matures. Many banks now offer online setup and ACH money transfers, although the paperwork to move an IRA is often more difficult.

The best source for finding bank deals is at DepositAccounts.com. There, you can see a list of all deals available for the length CD you want. Many deals are only for residents of certain states or cities, or people who have an affiliation with some employer or group.

Brokered CDs
Brokers sometimes can negotiate a higher interest rate on a bank-issued CD because they can bring a large amount of deposits to the bank. But, CDs sold by brokers can be complex and may carry more risks than traditional CDs sold directly by banks, especially in terms of your ability to lock in an attractive interest rate or get your money back early.

Because federal deposit insurance is limited to a total aggregate amount of $250,000 for each depositor in each bank or thrift institution, it is very important that you know which bank or thrift issued your CD. In other words, find out where the deposit broker plans to deposit your money. Your deposit broker may plan to put your money in a bank or thrift where you already have CDs or other deposits. You risk not being fully insured if the brokered CD would push your total deposits over the $250,000 federal deposit insurance limit.

Good account records by your deposit broker can ensure your CD will have federal deposit insurance and, in the event of a bank closing, you’ll be paid quickly. For example, unlike traditional bank CDs, brokered CDs are sometimes held by a group of unrelated investors. Instead of owning the entire CD, each investor owns a piece. Confirm with your broker how your CD is held, and be sure to ask for a copy of the exact title of the CD. If several investors own the CD, the deposit broker will probably not list each person's name in the title. But you should make sure that the account records reflect that the broker is merely acting as an agent for you and the other owners (for example, "XYZ Brokerage as Custodian for Customers"). This will ensure that your portion of the CD qualifies for full federal deposit insurance coverage.

Vanguard Brokerage Services
Vanguard (as well as other brokerage firms) offers brokered CDs from hundreds of different banks. All CDs available through Vanguard Brokerage Service are FDIC or NCUA insured (though you must stay below the limits). Interest payments (which are often made monthly) are deposited directly into the money market you have linked to your brokerage.

The downside is that the very best deals are not available as brokered CDs. So, you'll generally do better than your local bank but not as good as searching out the very best deals.