Money market accounts (MMAs) and certificates of deposit (CDs) may seem interchangeable. They are both bank products offering low yields with maximum peace of mind. However, choosing between them ultimately depends on the specific objective you have for the cash and your need for liquidity. Understanding the differences between the two is the key to determining which is the most appropriate vehicle for your needs.

Generally, there are a number of reasons to keep a portion of your assets in cash or these types of cash equivalents. A well-conceived financial plan dictates that you maintain an emergency fund worth three to six months of your living expenses. You can use MMAs and CDs to diversify your investment portfolio or fund a short-term goal.

How Money Market Accounts (MMAs) Work

An MMA is a type of mutual fund that invests in very short-term, interest-bearing instruments to generate a variable yield while preserving principal. It tends to deliver interest rates that are higher than savings accounts, but it often requires a higher minimum deposit. Some accounts also require a minimum balance to receive the highest rate.

The interest rates on MMAs are variable, which means that they rise and fall with the interest rate market. Most MMAs come with limited check-writing and balance-transfer privileges. What’s more, federal regulations limit the number of transactions in MMAs to six per month.

There are important differences between money market accounts offered by banks and money market funds offered by brokers or mutual funds. Money market funds are similar to MMAs, except that they aren't insured by the Federal Deposit Insurance Corp. (FDIC). Money market funds are typically offered as an option in 401(k) plans. Since 2016, these funds have had to be invested in U.S. Treasury or government bonds rather than corporate or municipal bonds. The change came courtesy of the U.S. Securities and Exchange Commission (SEC) to enhance liquidity and quality requirements.

How Certificates of Deposit (CDs) Work

CDs are best described as timed deposits that credit a fixed interest rate tied to a maturity date. A lengthier deposit period results in a higher rate of interest. CDs are issued with maturities that range in length from one month up to 10 years.

With traditional CDs, banks charge a penalty for withdrawing money prior to the maturity date. Some banks now offer no-penalty CDs that allow you to withdraw your money without that penalty, but you are likely to receive a much lower interest rate for that privilege. Other types of CDs allow you to withdraw only interest without penalty.

When an MMA Is Better than a CD

Generally, an MMA is better when you have or may have an immediate need for cash. If your car engine blows up, you wouldn't want to pay a penalty for prematurely withdrawing money from a one-year CD. If you have a near-term purchase planned, such as a new car or major appliance, an MMA provides greater flexibility from a liquidity standpoint.

MMAs may also be a better choice in a rising-interest-rate environment. Banks periodically adjust the yield on MMAs, offering the opportunity to earn more on your money as interest rates rise. However, you can achieve the same effect with higher yields by investing in short-term CDs and rolling them into higher-yielding CDs as they mature.

When a CD Is Better than an MMA

CDs usually offer a higher yield than MMAs. A longer maturity date means that you receive a higher interest rate. If you absolutely don’t have a need for the money, you could lock in a higher rate for a period of time. CDs are often used to fund goals within a 10-year time frame, when you may not want to risk the price fluctuation of market-based options, such as a stock mutual fund.

Although investing in longer-term CDs can secure a higher fixed interest rate, it would be a disadvantage during a period of rising interest rates. If you think that interest rates will rise for a period of time, you would be better off investing in shorter-term CDs. Some banks offer variable-rate CDs with rates that will increase as interest rates rise, but their initial yields tend to be lower than those of traditional CDs.

You could also employ a CD ladder strategy to balance your need for liquidity with obtaining higher yields. You could, for example, invest equal amounts in one-, two-, and three-year CDs. When the one-year CD matures, it rolls into a new three-year CD. After the two-year CD matures and has rolled into another three-year CD, you will then have a three-year CD maturing every year that follows.

Longer-term laddering might use five-year CDs, which can boost your average yield even higher. The net effect of the strategy is the ability to capture higher interest rates as the CDs mature while always staying invested and maintaining a degree of liquidity with CDs that mature each year.

The Bottom Line

Whether a CD or an MMA is better for a given investor depends on their time horizon and risk tolerance. CDs will generally pay higher interest than MMAs, especially for longer maturities. Both types of accounts are very safe, as they carry FDIC insurance up to $250,000 per account, but MMAs are much more liquid and don’t involve early withdrawal penalties.