Money market funds generate three types of taxable income

Money market funds pay tax on the interest they earn, and you owe tax on your share of that income whether the fund distributes it to you or reinvests it. The tax treatment depends on what the fund holds. Most money market funds invest in short-term debt issued by the U.S. government, corporations, or banks, and the interest from those investments is taxed as ordinary income at your regular tax rate — the same rate you pay on wages or salary.

Some money market funds focus on municipal bonds instead, which means the interest they earn is often exempt from federal income tax and sometimes from state tax too. A few funds hold a mix of both taxable and tax-exempt securities. The fund's prospectus tells you what percentage of its holdings are taxable versus tax-exempt, and that mix determines how much of your distribution is taxable.

You receive a tax form called a 1099-DIV each January for the prior year, showing how much taxable interest and tax-exempt interest the fund paid you. This is the number you report on your tax return, not the total amount you received (which may include your own principal being returned to you).

Key Takeaways

  • Interest from taxable money market funds is taxed as ordinary income at your full tax rate, not at a lower capital gains rate.
  • Municipal money market funds often pay interest that is exempt from federal income tax, making them useful for higher-income savers in high tax brackets.
  • You owe tax on your share of the fund's income in the year it is earned, even if you reinvest the distributions rather than withdraw them.
  • The fund sends you a 1099-DIV form showing taxable and tax-exempt interest; you use this to report income on your tax return.
  • Tax-exempt funds usually pay lower yields than taxable funds because investors are willing to accept lower returns in exchange for the tax break.

Taxable money market funds and ordinary income rates

When a money market fund invests in Treasury bills, commercial paper, or bank certificates of deposit, the interest it earns is taxable at your ordinary income tax rate. That rate depends on your filing status and total income for the year and ranges from 10% to 37% under current federal law. This is different from long-term capital gains, which are taxed at lower rates (0%, 15%, or 20%) — money market funds rarely generate capital gains because they hold short-term debt that matures quickly.

The yield on a taxable money market fund is what you see advertised — for example, 5.00% — but your actual after-tax return is lower. If you are in the 24% tax bracket and the fund yields 5.00%, your after-tax return is roughly 3.80%. Higher earners in the 35% or 37% brackets see even larger reductions. This is why comparing money market funds by their advertised yield alone can be misleading if you are in a high tax bracket.

Tax-exempt money market funds for higher earners

Money market funds that hold municipal bonds (short-term debt issued by states, cities, and local agencies) pay interest that is exempt from federal income tax. Some of these funds also hold bonds that are exempt from state income tax if you live in the state that issued them. The interest is still reported on your 1099-DIV, but you do not include it in your taxable income when you file your federal return.

Tax-exempt funds typically yield less than taxable funds — often 1% to 2% lower — because investors are willing to accept lower returns in exchange for the tax break. Whether a tax-exempt fund makes sense depends on your tax bracket. If you are in the 22% federal bracket or lower, the after-tax return on a taxable fund usually beats a tax-exempt fund. If you are in the 32% bracket or higher, a tax-exempt fund often comes out ahead. Your state tax rate matters too: if you live in a high-tax state like California or New York and buy a fund holding in-state bonds, the combined federal and state tax savings can be substantial.

How distributions are taxed when you reinvest them

Money market funds typically distribute interest monthly or daily. You can take that money out, or you can reinvest it by buying more shares of the fund. Either way, you owe income tax on the distribution in the year it is paid. The IRS does not care whether you spent the money or put it back into the fund — the tax is due on the income itself.

This is one reason money market funds are often held in tax-advantaged accounts like IRAs or 401(k)s, where distributions are not taxed until you withdraw the money (or never, in the case of Roth accounts). In a regular taxable account, the monthly distributions create a small tax bill every year, even if you are reinvesting everything and not touching the account.

Reporting money market fund income on your tax return

The fund company sends you a 1099-DIV form by January 31 showing the interest you earned in the prior calendar year. The form breaks down the income into categories: ordinary dividends (taxable interest), tax-exempt interest, and sometimes other types of income. You report the ordinary dividends on line 5b of your Form 1040 (or on Schedule B if you received more than $1,500 in interest from all sources). Tax-exempt interest goes on line 2a but is not added to your taxable income.

If you own shares in multiple money market funds, you receive a separate 1099-DIV from each one, and you add up all the ordinary dividends across all forms. Keep your 1099-DIV forms with your tax records for at least three years in case the IRS asks questions about your reported income.

State income tax on money market funds

Most states tax the interest from taxable money market funds at your regular state income tax rate, which ranges from 0% (in states with no income tax) to over 13% (in high-tax states). Some states exempt interest from U.S. Treasury securities, so a money market fund holding mostly T-bills may have a state tax advantage even if it is not a municipal fund.

Municipal bonds issued in your home state are usually exempt from both federal and state income tax. Bonds issued in other states are exempt from federal tax but subject to state tax in your home state. A few states (like Illinois and Iowa) exempt all municipal bond interest from state tax regardless of where the bond was issued. Check your state's tax rules and your fund's holdings to understand the full tax picture.

The impact of fund expenses on your after-tax return

Money market funds charge annual expenses (typically 0.10% to 0.50% of your balance) to cover management and administrative costs. These expenses reduce your return but do not reduce your taxable income — you still owe tax on the full interest the fund earned, even though some of that interest went to pay expenses. This is another reason to compare funds on their after-expense yield rather than their gross yield.

Ultra-low-cost money market funds with expense ratios below 0.10% are available from many large brokerages and fund companies. Over time, even a 0.20% difference in expenses compounds significantly, especially when combined with the tax drag on ordinary income. A fund yielding 5.00% with 0.50% in expenses and 0.50% in taxes leaves you with 4.00% after both costs.

Frequently Asked Questions

Do I owe tax on money market fund interest if I reinvest it?

Yes. The IRS taxes you on the interest in the year it is earned, regardless of whether you withdraw it or reinvest it in the fund. Reinvesting does not defer the tax — it only defers your access to the cash. To avoid annual tax bills, hold money market funds in an IRA or 401(k).

Is a tax-exempt money market fund always better than a taxable one?

No. Tax-exempt funds pay lower yields because of the tax break. If you are in a low tax bracket (10% or 12%), a taxable fund's after-tax return usually beats a tax-exempt fund. The crossover point is typically around the 22% bracket, but it depends on your state taxes and the specific funds you are comparing.

What if I buy a money market fund in December and it pays interest in January?

You owe tax on the interest paid in January, even though you owned the fund for only a few days. The fund company reports it on your 1099-DIV for the year you received it. This is why it sometimes makes sense to wait until after a distribution to buy a fund, to avoid a small tax bill for income you did not really earn.

Can I deduct money market fund losses on my taxes?

Money market funds rarely lose value because they hold short-term, low-risk debt. If you did sell shares at a loss, you could use that loss to offset capital gains or up to $3,000 of ordinary income in a single year. Losses beyond that carry forward to future years.

How do I know if a money market fund is taxable or tax-exempt?

The fund's name usually tells you — "tax-exempt" or "municipal" funds hold municipal bonds, while funds with no such label are taxable. The prospectus and fact sheet also state the fund's investment objective and the percentage of holdings that are tax-exempt. Your brokerage website shows this information too.