Money market funds are mutual funds that hold short-term debt instruments, not savings accounts
A money market fund is a type of mutual fund that invests in short-term borrowing instruments like Treasury bills, commercial paper, and certificates of deposit. It is not the same as a money market account, which is a bank product. The key difference: a money market fund is not insured by the Federal Deposit Insurance Corporation (FDIC), so your principal is not may provide. The fund's value can go down, though the decline is usually small because the underlying investments are very short-term and low-risk.
Money market funds aim to maintain a stable share price—typically $1 per share—while paying you interest. That interest comes from the earnings on the fund's holdings. The fund manager buys and sells short-term debt to keep the portfolio stable and competitive with current interest rates. Because the investments mature quickly (often within days or weeks), the fund can respond faster to rate changes than longer-term bond funds.
You buy money market fund shares through a brokerage account, mutual fund company, or retirement account. You can sell them at any time, though some funds may impose a small fee or require a minimum holding period. The fund sends you interest payments monthly or quarterly, depending on the fund's structure.
Key Takeaways
- Money market funds invest in short-term debt and aim to keep share price stable at $1, but they are not FDIC-insured and carry a small risk of loss.
- Interest rates on money market funds change with market conditions, so the yield you see today may be different next month.
- You buy and sell money market fund shares through a brokerage or mutual fund company, not through a bank.
- Money market funds are more liquid than bonds but typically pay less interest than longer-term investments.
How money market funds earn and pay interest
The fund manager invests your money in instruments that mature in one year or less. These include U.S. Treasury bills (issued by the federal government), commercial paper (short-term debt issued by corporations), and repurchase agreements (overnight loans between financial institutions). Each of these pays interest to the fund.
The fund collects that interest and subtracts its operating expenses—the fee the fund company charges to manage it. What remains is distributed to you as a dividend. If the fund holds $100 million in Treasury bills earning 5% annually, and the fund's expenses are 0.25% per year, the fund's yield to you would be roughly 4.75%. That yield changes as the fund's holdings mature and are replaced with new instruments at current market rates.
Most money market funds distribute income monthly, though some do it quarterly. You can choose to receive the payment in cash or reinvest it to buy more shares. Reinvestment compounds your returns over time.
The difference between money market funds and money market accounts
A money market account is a bank savings product insured by the FDIC up to $250,000. A money market fund is a mutual fund with no FDIC insurance. This is the most important distinction. If the bank fails, your money market account is protected. If the fund company fails or the fund's investments lose value, you could lose money.
Money market accounts typically have lower yields than money market funds because banks offer FDIC insurance and keep funds available for withdrawal. Money market funds can offer higher yields because they invest in a wider range of instruments and do not carry insurance. Money market accounts may also have withdrawal limits or require a minimum balance; money market funds usually do not.
Both are more liquid than longer-term savings vehicles like CDs or bonds. Both respond to interest rate changes faster than savings accounts. But if safety and insurance matter more to you than yield, a money market account is the better choice.
Expense ratios and how they affect your returns
Every money market fund charges an expense ratio—an annual fee expressed as a percentage of your investment. A fund with a 0.10% expense ratio charges $10 per year on every $10,000 you invest. A fund with a 0.50% expense ratio charges $50 on the same amount. Over time, even small differences add up.
Money market fund expense ratios typically range from 0.03% to 0.50% per year, depending on the fund company and the fund's size. Larger funds often have lower ratios because costs are spread across more investors. Index funds that track money market benchmarks tend to have lower ratios than actively managed funds.
When comparing money market funds, check the expense ratio first. If two funds hold similar investments and offer similar yields, the one with the lower expense ratio will put more money in your pocket. Over a decade, choosing a fund with a 0.10% ratio instead of a 0.50% ratio can mean hundreds of dollars in extra earnings.
When money market funds make sense in your savings plan
Money market funds work best for money you want to keep safe and accessible but do not need immediately. Common uses include holding an emergency fund, parking cash while you decide where to invest it, or keeping a portion of your portfolio in a low-risk holding. They are also useful if you want slightly higher returns than a savings account and can accept the small risk that comes with no FDIC insurance.
Money market funds are less useful if you need may provide returns or absolute safety. If you are saving for a specific goal with a known timeline—like a down payment in two years—a CD might be better because it locks in a rate. If you are building long-term wealth, stocks or longer-term bonds may offer better growth. If you cannot tolerate any risk to principal, a money market account or savings account is safer.
Money market funds also make sense as a temporary holding place during market volatility. If you sell stocks or bonds and want to wait before reinvesting, a money market fund lets you earn interest on the cash without locking it away.
Tax treatment of money market fund earnings
Interest paid by money market funds is taxed as ordinary income at your federal tax rate, the same as interest from a savings account or CD. If you earn $500 in interest from a money market fund and your tax bracket is 22%, you owe roughly $110 in federal tax on that income.
Some money market funds invest in municipal bonds, which pay interest that is exempt from federal income tax (and sometimes state tax too). These are called tax-exempt money market funds. They typically pay lower yields than taxable funds because the tax break makes them more valuable. Tax-exempt funds make sense only if you are in a high tax bracket and the after-tax yield is higher than a taxable fund.
If you hold a money market fund in a retirement account like a traditional IRA or 401(k), the interest is not taxed until you withdraw money from the account. In a Roth IRA, the interest is never taxed.
How to buy money market funds and what to watch for
You can buy money market funds through a brokerage account (Fidelity, Vanguard, Charles Schwab, etc.), directly from a mutual fund company, or through a retirement account. Most brokerages offer money market funds with no purchase fee. Some require a minimum investment, often $1,000 to $3,000, though some funds have no minimum.
When choosing a fund, compare the expense ratio, the current yield, and the types of investments the fund holds. A fund that invests only in Treasury securities is safer than one that holds commercial paper from many corporations. Read the fund's prospectus—the official document that describes what the fund invests in and how it operates—before you buy.
Watch for funds that promise higher yields than others. If a money market fund's yield is much higher than competitors, it may be taking on more risk by holding lower-quality debt or longer-term instruments. Stick with funds from established companies and those that hold high-quality, short-term debt.
Frequently Asked Questions
Can I lose money in a money market fund?
Yes, though it is rare. Because money market funds invest in very short-term debt, losses are usually small. A fund's share price can drop if the value of its holdings falls or if many investors withdraw money at once. FDIC insurance does not cover money market funds, so there is no government may provide of your principal.
How often do money market fund yields change?
Yields change as the fund's holdings mature and are replaced with new investments at current market rates. This can happen daily, but the yield you see quoted is usually an average over the past 30 days. When interest rates rise or fall, money market fund yields typically adjust within days or weeks.
Is a money market fund better than a savings account?
Money market funds usually pay higher interest than savings accounts, but they are not FDIC-insured. If you prioritize safety and do not mind lower returns, a savings account is better. If you want higher yields and can accept the small risk, a money market fund may be worth it.
Can I withdraw money from a money market fund anytime?
Yes, most money market funds allow you to sell your shares and withdraw the money within one to three business days. Some funds may impose a small fee or require a minimum holding period. Check the fund's rules before you invest.
What is the difference between a money market fund and a bond fund?
Money market funds invest in very short-term debt (under one year), while bond funds invest in longer-term debt (often several years). Bond funds offer higher potential returns but carry more risk and price volatility. Money market funds are more stable but pay less interest.