Money Market Funds vs High-Yield Savings: What Differs

A money market fund is a mutual fund that holds short-term debt; a high-yield savings account is a bank deposit. The practical differences are who stands behind the money (deposit insurance versus a regulated portfolio), how the rate is quoted (APY versus a 7-day yield), and how the income is taxed. Neither is better in every case, and the rate gap between them changes from week to week.

Key takeaways

Deposits in savings accounts and money market deposit accounts at FDIC-insured banks are insured up to $250,000 per depositor, per bank, per ownership category; money market mutual funds are not deposits and carry no FDIC insurance.
SIPC covers a money fund as a security if the brokerage fails, but it does not protect against a fall in the fund's value.
On October 22, 2026 the Crane 100 Money Fund Index showed a 7-day yield of 3.71%, while the FDIC's national savings rate was 0.38% on October 19, 2026; the national rate is an average of all institutions, so it says little about any single high-yield account.
In the hypothetical $25,000 example below, a government fund whose income is fully exempt from state tax earns about $66 more after tax than a savings account at an assumed 3.60% APY. That is a best case: with no state exemption, the gap is about $20.

What each product is

A money market mutual fund pools investors' cash and buys short-term, liquid debt such as Treasury bills, commercial paper and certificates of deposit. FINRA describes the main types as government funds, prime funds (mainly corporate debt) and tax-exempt funds (mainly state and local government obligations). Shareholders receive dividends that track short-term interest rates.

A high-yield savings account is an ordinary bank or credit union savings account that pays a higher rate than the typical account. A money market deposit account (MMDA) is also a bank deposit account, despite the similar name. FINRA notes that money market accounts at banks should not be confused with money market funds.

By the latest weekly data from the Investment Company Institute (ICI), money market funds held $7.94 trillion in the week ended October 21, 2026. Government funds accounted for $6.54 trillion of that (about 82%), prime funds $1.24 trillion and tax-exempt funds $0.16 trillion.

How the fund side is regulated

Funds follow SEC Rule 2a-7 (17 CFR 270.2a-7). Several of its definitions explain the differences between fund types:

Government fund: invests 99.5% or more of total assets in cash, government securities and fully collateralized repurchase agreements.
Retail fund: has policies reasonably designed to limit all beneficial owners to natural persons.
Tax-exempt fund: holds itself out as distributing income exempt from regular federal income tax.

Government and retail funds may use amortized-cost or penny-rounding pricing to hold a stable price, usually $1.00 per share. Funds that are neither (institutional prime and institutional tax-exempt funds) must price shares to at least four decimal places, so their price floats. Every fund must keep a dollar-weighted average maturity of 60 days or less. It may not buy anything other than daily liquid assets if that would leave less than 25% of total assets in them (a test that does not apply to tax-exempt funds), or anything other than weekly liquid assets if that would leave less than 50% in them.

The SEC's July 2023 reforms removed the gate provision that let funds suspend redemptions temporarily and added mandatory liquidity fees for some funds. Under the adopting release in the Federal Register, gates ended when the amendments took effect on October 2, 2023. Compliance with the higher liquidity minimums and the revised discretionary fee was required from April 2, 2024, and with the mandatory fee from October 2, 2024. The FAQ below gives the fee details.

Safety: insurance and its limits

The FDIC says deposit insurance covers $250,000 per depositor, per FDIC-insured bank, for each account ownership category. Savings accounts and MMDAs are covered. Stocks, bonds, mutual funds and other non-deposit investment products are not, even when an insured bank offers them. At a federally insured credit union, the NCUA share insurance fund provides the parallel protection.

A money fund has no such guarantee. FINRA states that, unlike many bank money market accounts, money market funds do not offer FDIC or NCUA protection. SIPC does not fill the gap: it protects the custody of cash and securities at a failed member brokerage, treats money market funds as securities, and does not protect against a decline in value.

The fund-side risk is not hypothetical. According to an SEC litigation release, the Reserve Primary Fund, which held $785 million in Lehman-issued securities, "broke the buck" on September 16, 2008, when its net asset value fell below $1.00 per share. FINRA adds that the fund froze redemptions and eventually liquidated. Rules have since tightened, and FINRA calls money funds one of the safest investments available to retail investors, but safe is not insured.

Yields: two dated benchmarks

The two products quote returns differently. A savings account quotes an annual percentage yield (APY), which includes compounding. A money fund quotes a 7-day yield: the net change in a hypothetical one-share account over seven days, divided by its starting value and multiplied by 365/7, as the SEC's Form N-MFP instructions describe for the gross figure.

The gross figure excludes shareholder fees and fund operating expenses; the net figure, reported by share class, is the one an investor lives with. It is a snapshot of recent income, not a promise.

Benchmark	Figure	Date	What it measures
FDIC national rate, savings	0.38%	October 19, 2026	Average of rates paid by all insured institutions and credit unions with data, weighted by domestic deposits
FDIC national rate, money market	0.63%	October 19, 2026	Same method
Crane 100 Money Fund Index	3.71%	October 22, 2026	Annualized 7-day current yield; an average of the 100 largest taxable money funds, government and prime

Sources: FDIC national rates and rate caps, Crane Data and Crane Data's description of the Crane 100.

The FDIC's national rate is a deposit-weighted average across thousands of institutions, so it is not what a high-yield account pays. The Crane 100 is a market-wide average, and Crane's published descriptions cited here do not say whether it is net of fund expenses, so it is a proxy rather than any one fund's net yield. The comparison that matters is the specific account's APY against the specific fund's net 7-day yield, both on the same day. The FDIC's national rates table has no separate high-yield savings figure, so the example below uses a labeled hypothetical rate.

Example: $25,000 for one year

Illustrative example. All rates are held constant for one year, which real rates will not do. The savings account is a hypothetical 3.60% APY. The fund uses the Crane 100 figure of 3.71% as a stand-in for one fund's net yield, treated as a simple annual rate.

Taxes assume 22% federal and 5% state on interest or dividends, with all fund income taxed as ordinary (non-qualified) dividends, ignoring state-tax deduction effects and any other taxes. In the last row, all of the fund's income is assumed to be exempt from state tax. That is a best case, which a real government fund may meet only in part or not at all (see State tax below).

pre-tax income = balance x rate
after-tax income = pre-tax income x (1 - tax rate)
tax rate = 22% federal + 5% state = 27%, or 22% when state-exempt

Case	Rate	Pre-tax income	Tax	After-tax income
Savings at FDIC national average	0.38%	$95.00	$25.65	$69.35
Hypothetical high-yield savings	3.60%	$900.00	$243.00	$657.00
Money fund, state tax applies	3.71%	$927.50	$250.43	$677.08
Government fund, state-exempt	3.71%	$927.50	$204.05	$723.45

The 0.11-point rate gap is worth $27.50 before tax and about $20 after tax. The state exemption is worth about $46 on its own (5% of $927.50), which makes it larger than the rate gap in this setup. Treating the fund's rate as simple slightly favors the savings account: with monthly reinvestment at 3.71%, pre-tax income would be about $943, or $16 more. A 0.20% expense ratio, by comparison, would cost $50 a year on $25,000, which is why the net 7-day yield is the figure to use; if a fund's net yield already reflects fees, do not subtract them again.

To test other balances or rates, the investment growth calculator can project a balance from any rate you enter; it does not model tax.

Access, timing and taxes

Access. A savings account moves money by bank transfer, on the bank's schedule. Federal law bars a fund from postponing payment for more than seven days after a redemption request, except when the NYSE is closed or trading on it is restricted, during an SEC-defined emergency, or when the SEC orders it. A money market fund can also suspend redemptions in order to liquidate, under SEC rule 22e-3, as the 2023 adopting release notes. Inside a brokerage account, timing also depends on the broker's sweep and settlement rules, so it is worth asking how many business days a sale takes to reach the linked bank.

Federal tax. The IRS lists interest on bank accounts and money market accounts as taxable interest, normally reported on Form 1099-INT; "dividends" on credit union share accounts are also taxable interest. IRS Publication 550 says amounts from money market funds should generally be reported as dividends, not as interest and that these funds should not be confused with bank money market accounts that pay interest. Fund dividends appear on Form 1099-DIV; all taxable dividends are ordinary income, and only the part the payer identifies as qualified is taxed at lower capital gain rates. Tax-exempt funds are different: FINRA says their income is generally exempt from federal income tax.

State tax. The IRS says Treasury bill, note and bond interest is exempt from state and local income tax, based on 31 U.S.C. 3124. A government money fund also holds repurchase agreements and agency securities, and each state decides how much of a fund's dividend keeps the exemption. California is one example: a 1996 State Board of Equalization decision describes Revenue and Taxation Code section 17145, under which a fund qualifies only if at least 50% of its total assets are exempt obligations, only the matching share of its dividends is exempt, the fund must designate them in a written notice, and income from repurchase agreements on federal securities is not exempt interest. Rules differ by state and can change, so the fund's year-end tax notice and the state tax agency's current guidance are the places to check.

Frequently asked questions

Can a money market fund lose money?

Yes. The stable $1.00 price is a target maintained under SEC rules, not a guarantee, and the Reserve Primary Fund fell below $1 in 2008. Institutional prime and institutional tax-exempt funds do not target a stable price at all; their share prices are rounded to four decimal places and can move.

What are liquidity fees and gates, and do gates still exist?

The July 2023 SEC reforms removed the provision allowing a temporary gate as of October 2, 2023, but a fund can still suspend redemptions permanently in order to liquidate, under SEC rule 22e-3. Under Rule 2a-7, with compliance required from October 2, 2024, a fund that is neither a government nor a retail fund must charge a mandatory liquidity fee when daily net redemptions exceed 5% of net assets. The fee is based on estimated selling costs, defaults to 1% if those cannot be estimated, and is not required if it would be under 0.01% of the amount redeemed. Non-government funds may also charge a discretionary fee of up to 2% if the board decides it serves the fund; government funds are exempt from that framework but may opt into it.

Does SIPC protect my money fund if my broker fails?

SIPC counts money market funds as securities and works to return missing securities and cash from a failed member brokerage, with a limit of $500,000 that includes $250,000 for cash. It does not protect against the fund losing value, and it is not the same as FDIC insurance.

Are credit union savings insured like bank savings?

At a federally insured credit union, NCUA share insurance covers individual accounts up to $250,000 and a member's interest in all joint accounts combined up to $250,000. IRA and Keogh accounts are separately covered up to $250,000. Coverage is automatic and does not require an application.

Can I compare a 7-day yield with an APY directly?

Only roughly. The 7-day yield annualizes seven days of income, using a 365/7 scaling factor, and changes as the fund's holdings reprice, while an APY is a bank's stated rate, which the bank can change. The SEC notes that 7-day gross yield excludes fees and expenses, so compare net yield with APY, on the same date, before tax.

Before choosing: a short checklist

Check the amount against the $250,000 limit for each bank and ownership category; larger balances may be better split across institutions or categories.
Identify the fund type (government, prime or tax-exempt) and whether it is a retail fund with a stable price.
Compare the fund's net 7-day yield with the account's APY, both dated the same day, and check the fund's expense ratio.
Run both after tax at your own federal and state rates, and ask whether any state exemption applies to the fund's actual holdings.
Confirm how quickly money moves between the account or fund and the bank where you spend it.