Money market funds are not bank accounts, and they are not insured the same way

A money market fund is a type of mutual fund—a pool of money managed by an investment company—not a deposit account at a bank. Because of that difference, the safety protections are different. Your money in a money market fund is not covered by FDIC insurance, which protects bank deposits up to $250,000. Instead, money market funds are regulated by the Securities and Exchange Commission (SEC) and held by a custodian bank, but the risk of loss falls on you as the investor.

This does not mean money market funds are unsafe. It means the safety comes from a different source: the quality and stability of the short-term debt the fund holds, not from a government may provide. A money market fund invests in very short-term loans—usually maturing in fewer than 90 days—to governments, corporations, and banks. These are considered low-risk because they are repaid quickly and the borrowers are usually large and stable.

The real risk in a money market fund is not that the borrower will default (though it can happen). The real risk is that the fund's value will drop slightly, or that you will not be able to withdraw your money as quickly as you expect. Both are rare, but both are possible.

Key Takeaways

  • Money market funds are not bank accounts and are not protected by FDIC insurance, so your principal is not may provide.
  • The safety of a money market fund depends on the quality of the short-term debt it holds, not on a government backstop.
  • A money market fund can lose value if interest rates rise sharply or if a major borrower defaults, though this is uncommon.
  • During financial crises, money market funds have sometimes frozen withdrawals or "broken the buck" (fallen below $1 per share), which happened most notably in 2008.
  • Money market funds are best suited for money you need to keep liquid and safe but do not need to access instantly, and for which you accept a small risk of loss in exchange for a higher yield than a savings account.

What happens if a borrower in the fund defaults

When a money market fund holds short-term debt, it is betting that the borrower will repay on time. Most of the time, they do. But if a major borrower—say, a large bank or corporation—fails to repay, the fund's value drops. The loss is spread across all shareholders in the fund, so your share of the loss depends on how much money you have in the fund and how large the default is relative to the fund's total assets.

In practice, defaults in money market funds are rare because the fund manager deliberately chooses borrowers with very low default risk. The fund also holds many different borrowers, so no single default wipes out the fund. But rare is not the same as impossible. During the 2008 financial crisis, one major money market fund called the Reserve Primary Fund held debt from Lehman Brothers, which collapsed. The fund's value fell below $1 per share—an event called "breaking the buck"—and investors lost money.

Interest rate risk and fund value changes

Money market funds are sensitive to interest rate changes in a way that savings accounts are not. When the Federal Reserve raises interest rates, new short-term debt pays higher yields. The debt already in the fund pays the old, lower rate. This makes the fund's existing holdings less attractive, and the fund's share price can drop slightly to reflect that.

The opposite happens when rates fall. New debt pays lower yields, so the fund's existing holdings become more valuable. The share price can rise slightly. These moves are usually small—often less than 0.1 percent—but they are real, and they mean the fund's value is not fixed the way a bank savings account is.

This is why money market funds are called "stable value" funds rather than "fixed value" funds. The value is stable most of the time, but it can move.

Liquidity risk: when you cannot withdraw as fast as you expect

Money market funds are supposed to be highly liquid—meaning you can withdraw your money quickly. In normal times, you can usually get your money within one or two business days. But during financial stress, the fund manager can impose restrictions. The SEC allows money market funds to temporarily freeze withdrawals or charge a fee to withdraw if the fund's liquid assets fall below a certain threshold.

This happened during the 2008 crisis and again briefly in 2020 when the pandemic hit. Investors who thought they could access their money on demand suddenly could not, or could only withdraw a portion. For someone who needs cash urgently, this is a serious problem. For someone who is using a money market fund as a place to park money for a few months, it is an inconvenience.

How money market funds are regulated and monitored

The SEC sets rules for how money market funds operate. These rules limit what kinds of debt the fund can hold, how short the maturity must be, and how diversified the holdings must be. The fund manager must also maintain a certain amount of very liquid assets—cash or debt maturing within one day—so that withdrawals can be processed quickly under normal conditions.

The fund is also held by a custodian bank, which keeps the actual securities separate from the fund company's own money. If the fund company fails, your securities are still yours and are not at risk. This is different from a bank failure, where deposits are protected by FDIC insurance, but it is still a meaningful protection.

That said, regulation does not eliminate risk. It reduces it and makes it more transparent. A well-regulated money market fund is safer than an unregulated investment, but it is not risk-free.

Comparing money market funds to money market accounts

Do not confuse a money market fund with a money market account. A money market account is a type of bank deposit account that is FDIC-insured up to $250,000. It usually pays a higher interest rate than a regular savings account but may require a higher minimum balance or limit the number of withdrawals per month. Your principal is may provide.

A money market fund is a mutual fund that invests in short-term debt. It is not FDIC-insured, and your principal is not may provide. But it usually pays a higher yield than a money market account because it carries more risk.

If safety is your top priority and you do not need the highest possible yield, a money market account is the better choice. If you are willing to accept a small amount of risk in exchange for a higher return, and you do not need instant access to your money, a money market fund may make sense.

When a money market fund makes sense for you

A money market fund is most useful for money you want to keep safe and liquid but do not need to access instantly. Examples include an emergency fund that you plan to keep for six months to a year, or money you are saving for a down payment on a house and do not plan to touch for several months.

A money market fund is less useful if you need the money within days, because you might face withdrawal restrictions during a market stress event. It is also less useful if you are very risk-averse and cannot tolerate any possibility of loss, because FDIC-insured accounts offer that may provide.

Before you invest in a money market fund, read the fund's prospectus—the official document that describes what the fund holds, what fees it charges, and what risks it carries. The prospectus will tell you the fund's average maturity, its credit quality, and what percentage of its holdings are in each type of debt. A fund that holds mostly U.S. Treasury debt is safer than one that holds mostly corporate debt. A fund with an average maturity of 30 days is less sensitive to interest rate changes than one with an average maturity of 60 days.

Frequently Asked Questions

Can I lose all my money in a money market fund?

Losing all your money is extremely unlikely. Money market funds hold very short-term, low-risk debt, and they are diversified across many borrowers. But you can lose some money if a major borrower defaults or if the fund breaks the buck, as happened in 2008. The loss is usually small—often less than 1 percent—but it is possible.

Is a money market fund safer than a savings account?

A savings account is safer because it is FDIC-insured and your principal is may provide. A money market fund offers a higher yield but carries the risk of small losses. Choose a savings account if safety is your only concern; choose a money market fund if you are willing to accept a small risk for a higher return.

What happens to my money market fund if the stock market crashes?

A money market fund is not directly affected by stock market crashes because it does not hold stocks. However, a severe financial crisis can cause borrowers to default and can trigger withdrawal restrictions. During the 2008 crisis, some money market funds lost value even though the stock market was the main source of the panic.

How much does a money market fund typically pay?

Money market fund yields change daily based on interest rates and the fund's holdings. In recent years, yields have ranged from near zero to over 5 percent, depending on what the Federal Reserve is doing with interest rates. Check the fund's current yield before you invest, and remember that past yields do not predict future ones.

Can the fund manager change what the fund invests in?

Yes, within the limits set by the SEC. The fund manager decides which borrowers to lend to and which debt to hold. This is why it matters which fund you choose—different funds have different managers and different strategies, which means different risk profiles and different yields.