Money market mutual funds are safer than stocks but not risk-free, and they pay less because of it

A money market mutual fund invests in short-term debt — Treasury bills, commercial paper, and certificates of deposit that mature in less than a year. Because these loans are short-term and issued by stable borrowers, the fund's value stays close to $1 per share. You will not see the wild swings you get with stock funds. But "close to $1" is not the same as "exactly $1", and the fund can lose money if the borrower defaults or interest rates move sharply.

The real trade-off is simpler than it sounds: money market funds are safer than stocks, but they return less. In recent years, they have paid around 4 to 5 percent annually, while the stock market has averaged roughly 10 percent over long periods. You are paying for stability with lower returns. Whether that trade-off makes sense depends on why you are holding the money and when you might need it.

Key Takeaways

  • Money market mutual funds hold short-term debt from stable borrowers and rarely lose value, but they can if a borrower defaults or rates shift sharply.
  • The fund's share price stays near $1, so you see steady, predictable returns instead of the ups and downs of stock funds.
  • Current money market fund yields are typically 4 to 5 percent annually, lower than long-term stock returns but higher than savings accounts.
  • Your money is not insured by the FDIC — the fund itself can fail, though this is rare — so money market funds carry more risk than bank savings accounts.
  • Money market funds work best for money you need within one to three years or cash you want to keep stable while deciding where to invest it.

How money market funds stay stable in price

Money market funds hold only short-term loans — most mature within 90 days. Because the loans are short, interest rate changes do not swing the fund's value the way they do with bonds. When a loan matures, the fund gets its money back and buys a new one at the current rate. The fund manager also buys only from borrowers with high credit ratings, usually the U.S. government, large banks, and big corporations.

This strategy keeps the share price hovering around $1. You will not see your $10,000 drop to $9,500 overnight the way it might in a stock fund. Instead, the fund pays you interest — usually monthly or quarterly — and your share price stays steady. That stability is the main reason people hold money market funds: you know roughly what you will have at any given time.

The real risks money market funds face

The biggest risk is credit risk — the chance that a borrower defaults. If a bank or corporation that issued commercial paper fails, the fund loses money on that holding. This is rare because fund managers stick to highly rated borrowers, but it has happened. During the 2008 financial crisis, one money market fund "broke the buck" — its share price fell below $1 — when Lehman Brothers collapsed and the fund held its debt.

A second risk is interest rate risk. If rates rise sharply, the value of the fund's existing holdings falls (though the fund does not usually sell them, so you do not see the loss unless you sell your shares). If rates fall, the opposite happens — the fund's holdings gain value, but new money coming in earns less. This is a smaller problem for money market funds than for bond funds because the loans are so short, but it still exists.

The third risk is liquidity risk — the chance that you cannot sell your shares when you want to. During extreme market stress, some money market funds have temporarily frozen redemptions to prevent a run. This is extremely rare and usually lasts only days, but it can happen.

Money market funds versus bank savings accounts

A bank savings account is insured by the FDIC up to $250,000 per account holder per bank. If the bank fails, you get your money back. A money market mutual fund is not insured by the FDIC. If the fund fails or a major borrower defaults, you lose money. The fund itself is regulated by the SEC, and fund managers must follow strict rules about what they can hold, but regulation is not the same as insurance.

In exchange for that extra risk, money market funds currently pay more than savings accounts. A typical savings account pays 0.01 to 0.5 percent annually, while money market funds pay 4 to 5 percent. If you need the money within a year and can tolerate the small risk of default, the higher return makes sense. If you need absolute safety and do not mind the lower rate, a savings account is the right choice.

When money market funds make sense

Money market funds work well for money you plan to spend within one to three years — a down payment you are saving for, an emergency fund you want to earn more than a savings account, or cash you are holding while deciding where to invest it long-term. They also make sense if you want to reduce the stock portion of your portfolio without moving to bonds, which carry their own risks.

They do not make sense for money you need immediately — keep that in a checking account. They also do not make sense for money you will not touch for 10 or 20 years, because stocks have historically returned more over long periods, and you have time to ride out the ups and downs.

How to evaluate a specific money market fund

If you are considering a money market fund, look at three things. First, check the expense ratio — the annual fee the fund charges. Money market funds typically charge 0.2 to 0.5 percent per year. A lower ratio means more of your return stays in your pocket. Second, look at the fund's yield — what it has paid recently. Yields change with interest rates, so compare funds that are similar in type (government funds versus prime funds, for example).

Third, check what the fund holds. Some money market funds invest only in U.S. Treasury securities, which carry almost no credit risk but pay less. Others invest in commercial paper from corporations, which pay more but carry default risk. The fund's prospectus lists what it holds and the credit ratings of its holdings. A fund that holds mostly highly rated debt is safer than one that stretches into lower-rated paper to chase yield.

What happened to money market funds during past crises

Money market funds have weathered most financial stress without breaking the buck. During the 2008 crisis, the government stepped in to may provide money market fund holdings, which prevented widespread panic. Since then, the SEC has tightened rules: funds must hold more of their assets in very liquid securities, and they can impose fees or temporarily freeze redemptions if stress occurs.

These changes make money market funds safer than they were before 2008, though not risk-free. The 2020 COVID-19 market shock caused some stress but no breaks. The 2023 banking crisis — when Silicon Valley Bank and others failed — did not directly hit money market funds because they do not hold bank deposits the way banks do, though it did remind investors that financial institutions can fail.

Frequently Asked Questions

Can a money market fund lose all my money?

Extremely unlikely. A money market fund would have to suffer multiple major defaults at once to lose more than a small percentage of its value. The 2008 crisis produced only one break-the-buck event out of thousands of funds. That said, it is not impossible — the fund is not insured like a bank account is.

Is a money market fund better than keeping cash in a checking account?

If you do not need the money for at least a few months, a money market fund usually pays more. A checking account pays almost nothing; a money market fund currently pays 4 to 5 percent. The trade-off is that you cannot access the money instantly — it takes a day or two to sell shares — and you carry a small default risk. For emergency money you might need tomorrow, a checking account is better.

Do I pay taxes on money market fund earnings?

Yes. The interest the fund pays is taxed as ordinary income in the year you receive it, at your regular tax rate. If the fund is in a tax-deferred account like an IRA, you do not pay taxes until you withdraw. If it is in a regular brokerage account, you owe taxes annually, even if you reinvest the earnings.

What is the difference between a government money market fund and a prime money market fund?

A government money market fund holds U.S. Treasury securities and agency debt, which carry almost no default risk but pay less. A prime money market fund holds commercial paper from corporations and banks, which pay more but carry credit risk. Government funds are safer; prime funds offer higher returns.

Should I move my emergency fund to a money market fund?

It depends on how much you might need and how fast. If your emergency fund is three to six months of expenses and you can wait a day or two to access it, a money market fund makes sense — you earn 4 to 5 percent instead of nearly nothing. If you might need it within hours, keep it in a savings or checking account. Some people split the difference: keep one month in checking, the rest in a money market fund.