Money Market Fund vs HYSA (2026), Yield, Tax & Risk Compared
Quick take: Top money market funds and top high-yield savings accounts run within 30-80 bps of each other. The MMF reprices to the Fed within 2-4 weeks; the HYSA APY is set by the bank and tends to lag both up and down. MMFs are SEC-regulated mutual funds with no FDIC insurance; HYSAs are FDIC-insured to $250K. Pick on after-tax yield, sleep-at-night, and what's already inside your brokerage.
| Product | Yield / APY | Source, as of |
|---|---|---|
| Vanguard Treasury MMF (VUSXX) | 3.76% | vanguard.com, 09/24/2026 |
| Schwab Prime Advantage (SWVXX) | 3.70% | schwabassetmanagement.com, 09/25/2026 |
| Schwab Government (SNVXX) | 3.57% | schwabassetmanagement.com, 09/25/2026 |
| Fidelity Government MMF (SPAXX) | 3.46% | fidelity.com, 09/24/2026 |
| Vanguard Federal MMF (VMFXX) | 3.74% | vanguard.com, 09/23/2026 |
| Live Oak Bank Personal Savings | 4.00% APY | liveoak.bank, 9/8/2026 |
| Sallie Mae High-Yield Savings | 3.85% APY | salliemae.com, 09/24/2026 |
| Ally Online Savings | 3.00% APY | ally.com, 09/24/2026 |
MMF figures are 7-day yields; bank figures are APYs. Both change without notice.
Money market fund vs MYGA, after tax
What $100,000 earns in 5 years: money market fund vs MYGA, after tax
Rates used: Money market fund 3.76%, the highest 7-day yield we tracked (VUSXX, fund sites, September 23, 2026); yields change daily; change it to the rate you are offered. MYGA 5.95%, the best A-rated rate we track as of October 13, 2026: Delaware Life Pinnacle Plus 5-year (AM Best A-, negative outlook, 7/31/2026), $100,000 and up, effective October 6, 2026 (Delaware Life rate sheet).
| Money market fund, interest taxed every year | $115,550 |
|---|---|
| MYGA, tax-deferred, before tax | $133,507 |
| MYGA after paying tax on all the interest at withdrawal | $126,136 |
| Tax deferral alone adds about | $674 |
| MYGA ahead of the money market fund, after tax | $10,586 |
Assumes 22% federal and 0% state income tax, no withdrawals, rates held for the whole term. MYGA interest is taxed as ordinary income when you withdraw it, not as capital gains. Gains taken before age 59 1/2 can owe a 10% IRS penalty, and cashing out early can cost a surrender charge. In an IRA both grow tax-deferred, so the edge there is the rate alone. A MYGA is backed by the issuing insurer's claims-paying ability and your state's guaranty association up to its limits, not the FDIC. General education, not tax, legal or financial advice.
Side-by-side, MMF vs HYSA
| Feature | Money Market Fund | High-Yield Savings Account |
|---|---|---|
| Top yield (checked Sept 23-25, 2026) | 3.45-3.76% (7-day yield, major funds) | 3.00-4.00% APY (major online banks) |
| Yield measurement | 7-day SEC yield (backward-looking 7 days) | APY (compounded annual yield) |
| Insurance | None (SEC 2a-7 regulated) | FDIC-insured to $250K per depositor per bank |
| Yield response to Fed cuts | 2-4 weeks (very fast) | 1-3 months (banks lag) |
| Yield response to Fed hikes | 2-4 weeks (very fast) | 1-6 months (banks lag, favorably) |
| Liquidity | Same-day inside brokerage | Next-day to 3-day external transfer typical |
| State-tax treatment | Government/Treasury MMFs: partial-to-full state-tax exemption | Fully state-taxable |
| Federal tax treatment | Ordinary income | Ordinary income |
| "Breaking the buck" risk | Twice in history; both edge cases | None (FDIC backstops $250K) |
| Lockup | None | None |
Rates expire like milk.
The best MYGA, CD and savings rates change every few weeks. Get a short email when a rate on this page changes.
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The 7-day yield vs APY apples-to-oranges trap
MMFs report a 7-day SEC yield: the annualized net yield earned over the prior 7 days. HYSAs report APY: a forward-looking annualized yield assuming the current rate holds for a full year, with compounding.
They are not directly comparable. The 7-day yield is roughly equivalent to the SEC's 7-day "simple" yield (no compounding assumption). The 7-day "compound" yield is slightly higher than the simple yield because it assumes the dividend is reinvested.
In practice, the differences are usually within 5-10 bps and not large enough to flip a decision. The headline rule of thumb: if you see a 4.30% MMF 7-day yield and a 4.30% HYSA APY, they are approximately equivalent before tax.
After-tax math, CA resident, $100,000 cash
| Vehicle | Stated Yield | Federal-Taxable | State-Taxable | After-Tax @ 32% Fed + 9.3% CA |
|---|---|---|---|---|
| VUSXX (Treasury MMF, 09/24/2026) | 3.76% | 100% | ~2% | ~2.55% |
| VMFXX (Government MMF, 09/23/2026) | 3.74% | 100% | ~45% | ~2.39% |
| SWVXX (Prime MMF, 09/25/2026) | 3.70% | 100% | 100% | ~2.17% |
| HYSA (Sallie Mae, 09/24/2026) | 3.85% | 100% | 100% | ~2.26% |
For a California resident, the after-tax yield ranking flips the headline ranking. The Treasury MMF (3.76%) trails the 3.85% HYSA before tax but delivers the highest after-tax yield (about 2.55% vs 2.26%) because the state-tax exemption is worth roughly 35 bps in that bracket.
When the MMF wins
- You already have brokerage cash. Sweeping into a MMF inside your existing brokerage is zero-friction. Moving to an external HYSA requires ACH setup and 1-3 day transfer delays.
- You live in a high-state-tax state. A Treasury MMF with 95-100% state-tax exemption beats every HYSA after tax.
- The Fed is hiking. MMFs catch hikes within weeks; banks raise HYSA APYs at their leisure (often 1-3 months later).
- You want a single tax form. One 1099-DIV vs. potentially multiple 1099-INTs from a HYSA bonus-rate-shopping rotation.
When the HYSA wins
- You want FDIC insurance. $250K of FDIC coverage per depositor per bank. No "breaking the buck" risk, ever.
- The Fed is cutting. Banks lag rate cuts, you keep earning the old higher APY for weeks or months after the MMF has already repriced down.
- You don't have a brokerage account. HYSAs require no brokerage; MMFs do.
- You want a hard separation between checking and savings. An external HYSA at a different bank creates intentional friction that helps with budgeting discipline.
The vehicle that beats both for 3+ year money
The MMF-vs-HYSA debate matters for cash you might need in 6-18 months. For money you reliably won't touch for 3-5 years, both vehicles are wrong. A-rated 5-year MYGAs topped out around 5.50-6.05% on October 14, 2026 (public carrier rate sheets), locked for the full term, roughly 180-250 bps over the MMF and HYSA yields checked the same week, with tax deferral. See MMF vs MYGA →
More Money Market Fund research
- Best Money Market Funds 2026 (ranked)
- MMF vs MYGA, when each wins
- MMF vs HYSA, yield spread and risk
- MMF vs CD, liquidity vs lock
- Breaking the buck, 1994 & 2008 cases
- How MMF yields track the Fed funds rate
- High-Yield Savings reviews
- Best MYGA rates 2026
FAQ
Q: Can a MMF really "break the buck"?
A: Twice in U.S. history a money market fund has dropped its NAV below $1.00: the Community Bankers U.S. Government Money Fund in 1994 (lost ~4%, fund was wound down) and the Reserve Primary Fund in 2008 (lost ~3% on Lehman exposure, triggered the broader MMF run that the Fed had to backstop). Both were edge cases. Government and Treasury MMFs in 2026 are dramatically safer than 2008 prime funds were.
Q: Is FDIC insurance worth the yield gap?
A: For most balances, no, the practical safety difference between a government MMF and an FDIC-insured HYSA is invisibly small. For balances above $250K that you want fully covered without splitting across multiple banks, FDIC is the cleanest answer.
Q: Why do HYSA APYs lag the Fed?
A: Banks have discretion to set deposit rates; MMFs reprice mechanically as portfolio holdings mature and roll. Banks raise APYs slowly to retain the spread (their net interest margin). They cut APYs quickly when the Fed cuts. The asymmetry is real.
Q: Should I have both?
A: Yes, often. Many retirees keep an HYSA for the emergency-fund slug (immediate FDIC-backed accessibility) and a brokerage MMF for the larger short-term cash reserve. Different jobs, different vehicles.
About Hans Goldstein: Independent retirement income specialist. CA Life License #4273294. NPN #20602398. Reviews 30+ carriers and the full menu of cash alternatives. Phone: 213-414-2808. Email: hans@hansgoldstein.com.
Hans is independently licensed as an insurance producer; he does not sell money market funds or other securities. These reviews are based on publicly available fund prospectuses, fact sheets, SEC filings, and SEC-yield reporting requirements.
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Money market funds are great for short-term cash. For money you don't need for 3+ years, a multi-year guaranteed annuity (MYGA) typically pays 100-150 bps more and defers tax. Get an independent side-by-side before you let cash drift in a MMF for 5 years.
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Disclosure
This review reflects publicly available fund prospectuses, fact sheets, and approximate 7-day SEC yields as of the date stated above. Money market fund yields change daily and reset roughly in line with the federal funds rate; always confirm current yield, expense ratio, holdings, and weighted average maturity against the most recent fund disclosure document before committing capital. Money market funds are not FDIC-insured. Government and Treasury money market funds historically maintain a stable $1.00 NAV but are not guaranteed to do so, see "breaking the buck" history. Prime money market funds may impose liquidity fees or redemption gates during market stress. This is general education, not a personal recommendation or an offer of any product. Hans Goldstein is an independent licensed insurance producer (NPN 20602398) and does not sell securities or money market funds; comparisons to multi-year guaranteed annuities (MYGAs) are provided for informational context only. No compensation has been received from any fund company in connection with the publication of this review. Always read the actual fund prospectus and consult a licensed advisor before investing. Past yield does not predict future yield. State income tax treatment of U.S. Treasury obligations varies and is subject to change. Tax discussion reflects federal and California law as of 2026 and is subject to change.