Money market funds spent years as an afterthought — a parking lot earning nothing while you waited for something better to buy. That changed when interest rates rose to levels that made real income possible on cash. In 2026 they remain a legitimately useful tool for liquid savings, but the differences between funds matter more than most people assume.
What changed in 2026
- Yields remain meaningfully above zero. Government money market funds are generating real after-inflation income for the first time in years, making them a genuine component of a cash strategy.
- Reform guardrails matured. Post-2023 SEC reforms introduced swing pricing and liquidity buffers that make institutional runs less likely to affect retail investors.
- Brokerage default cash sweeps shifted. Several major brokerages now automatically sweep uninvested cash into money market funds rather than low-yield bank programs — check your default and compare it.
- Tax-exempt funds regained attention as investors in the 32–37% brackets recalculate after-tax yields.
Fund types explained
| Fund type |
Underlying assets |
Best for |
| Government |
US Treasuries + agency securities |
Emergency fund, core cash — lowest risk |
| Treasury-only |
Strictly US Treasuries |
State-tax-free income (where applicable) |
| Prime |
Mix of Treasuries, agencies, corporate paper |
Slightly higher yield, slightly more credit risk |
| Tax-exempt (muni) |
Short-term municipal bonds |
High-bracket investors seeking tax-free income |
Key metrics to compare
7-day yield (annualized): The standard yield metric for money market funds. Use this for apples-to-apples comparison — not the 30-day yield, which lags.
Expense ratio: Comes directly out of your yield. A fund yielding 5.0% gross with a 0.35% expense ratio nets 4.65%. A competing fund at 5.0% gross and 0.10% nets 4.90%. That 0.25% gap compounds.
Minimum investment: Institutional share classes often require $1M+. Retail share classes typically start at $1–$3k. Some brokerage-specific share classes have $0 minimums for account holders.
Portfolio weighted average maturity (WAM): Shorter WAM means faster repricing when rates change. In a falling-rate environment, longer WAM is better; in rising, shorter.
How to pick
- Decide on safety tier first. For cash you cannot afford to lose value on — emergency fund, near-term purchase — use government or Treasury-only. For longer-duration cash reserves, prime is acceptable.
- Compare 7-day yield net of expense ratio. The gross number is marketing; the net number is your return.
- Check your tax situation. If you are in a 32%+ bracket, run the tax-equivalent yield calculation for municipal money market funds. A 3.5% tax-free yield can beat a 5.0% taxable yield.
- Confirm the fund is available in your account. Many of the best-yielding funds are only accessible through specific brokerages.
- Review the brokerage default. If your cash sweeps automatically into a fund, know which one and what it yields — defaults are often not the highest-yielding option.
Common mistakes
Using the 30-day yield for comparison. It lags changes in the fund's holdings. Always compare the 7-day SEC yield.
Ignoring expense ratios. A fund with a higher gross yield and a higher expense ratio may net less than a "lower yield" fund with low fees.
Treating prime funds as equivalent to government funds. Prime funds hold corporate commercial paper. In a credit stress event, NAV can fluctuate — small risk, real distinction.
Holding too much in money market funds. Cash earns real returns now, but it still trails long-run equity returns. Hold what you need liquid; invest the rest.
What to skip
- Brokerage default sweep accounts without verifying the yield — some are still low-yield bank programs from the old rate era.
- Prime funds for your emergency reserve — government is the right risk profile for money you must access at par.
- Funds with high minimum investments you cannot meet — the retail share class of a good fund beats the institutional share class of a fund you cannot access.
FAQ
Are money market funds FDIC insured?
No. They are securities, not bank deposits. Government money market funds are extremely low risk, but not insured. Money market accounts at banks are FDIC insured — a different product.
Can the NAV drop below $1?
It is rare and structurally limited. Government money market funds have essentially never "broken the buck." Prime funds have, in extreme stress scenarios.
How do I access money market funds?
Through a brokerage account. Most major brokerages offer proprietary or third-party money market funds with no transaction fees for account holders.
How quickly can I redeem?
Government money market funds typically settle same-day or T+1. Check the fund's redemption terms before relying on it for immediate liquidity.
Where to go next
See What is a money market account in 2026, Best high-yield CDs in 2026, and Saving vs investing in 2026.