Comparison Last updated: 2026-06-27 By: Hans Goldstein, NPN 20602398

HYSA vs Money Market Fund (2026) - VMFXX, SPAXX, Safety, Yield

Quick take: HYSAs (bank deposits) and Money Market Funds (mutual funds) are often confused but legally distinct. HYSA: FDIC-insured to $250K, simple savings. MMF (Vanguard VMFXX, Fidelity SPAXX, Schwab SWVXX): mutual fund of short-term Treasuries/repo, NOT FDIC-insured, SIPC-covered for fraud only. In 2026, top MMFs pay 5.10-5.25% gross (slightly above HYSAs).

HYSA top

~4.55%

VMFXX yield

~5.20%

FDIC (HYSA)

$250K

SIPC (MMF)

$500K fraud-only

The legal structure difference

Feature	HYSA	Money Market Fund
What it is	Bank deposit	Mutual fund of short-term debt
Issuer	FDIC-insured bank	Asset manager (Vanguard, Fidelity, Schwab)
Insurance	FDIC $250K per depositor per bank	SIPC $500K (incl $250K cash) - fraud only, not investment loss
Current yield (2026)	4.10-4.55% APY	5.10-5.25% 7-day SEC yield (gross)
"Breaks the buck" risk	No - principal protected by FDIC	Very rare but possible - Reserve Primary 2008
Liquidity	Same-day to next-day via ACH	Same-day via brokerage; T+1 settle to bank
Tax: federal	Ordinary income, taxed annually	Ordinary income (dividends), taxed annually
Tax: state	Fully taxable in most states	Treasury portion typically state-tax-exempt
Expense ratio	0% (bank earns the spread)	0.10-0.45%

The three big money market funds

Vanguard Federal Money Market Fund (VMFXX)

7-day SEC yield: ~5.20% (2026)
Expense ratio: 0.11%
Holdings: ~80% US Treasuries + repo, 20% government agency
State tax: ~50-70% of dividends typically state-exempt (Treasury portion)
Minimum: $3,000 initial
The default settlement fund in most Vanguard brokerage accounts

Fidelity Government Money Market Fund (SPAXX)

7-day SEC yield: ~5.10% (2026)
Expense ratio: 0.42%
Holdings: similar Treasury + repo mix
State tax: similar partial exemption
Minimum: $0 (auto-sweep for Fidelity brokerage cash)
Auto-sweep is the convenience advantage at Fidelity

Schwab Government Money Market Fund (SWVXX)

7-day SEC yield: ~5.15% (2026)
Expense ratio: 0.34%
Holdings: Treasury + repo
State tax: similar partial exemption
Minimum: $0
Schwab has a Bank Sweep alternative paying 0.45% - explicitly compare before defaulting

Worked example: $100,000 in HYSA vs VMFXX

32% federal + 9.3% CA bracket. VMFXX assumes 50% of dividends are Treasury-exempt at state level (so the 9.3% CA tax applies to only half).

Vehicle	Gross yield	Federal tax	State tax	Net yield	Net annual
HYSA @ 4.30%	4.30%	32% on full	9.3% on full	2.52%	$2,520
VMFXX @ 5.20% (50% state-exempt)	5.20%	32% on full	9.3% on half	3.29%	$3,290
VMFXX advantage	+90 bps	-	State exemption	+77 bps	+$770/yr

VMFXX wins by $770/yr on $100K after tax in a CA high bracket - a meaningful pickup for the same risk profile (both extremely safe, both fully liquid). In a no-state-tax state (TX, FL, WA), the gap is smaller (state exemption is irrelevant).

The risk asymmetry to understand

HYSAs cannot lose principal under FDIC. Period. Even if Marcus disappeared tomorrow, your $250K is whole.

MMFs CAN lose principal in rare stress events. Reserve Primary Fund (2008) returned ~$0.99/share after Lehman collapse. 2023 reforms (liquidity fees, gated redemptions in stress) make government MMFs extremely robust - but the failure mode exists.

For ordinary households, this risk is essentially theoretical. For institutional cash management, it matters. The 90 bps yield premium reflects this risk asymmetry.

The convenience factor

If you already manage a Vanguard, Fidelity, or Schwab brokerage account, putting cash in the settlement MMF takes one click. If you don't, opening a brokerage adds operational complexity (transfer setup, tax form management, learning curve).

Most retail savers should default to HYSA for simplicity. Brokerage-comfortable savers should consider MMF for the yield + state tax pickup.

What about for 3+ year money?

Neither HYSA nor MMF locks the rate. Both are variable, Fed-driven. When the Fed cuts, both yields drop in lockstep. For 3+ year money where you want rate certainty, neither is the right tool - a MYGA at 5.40-5.65% locked, tax-deferred, clears both after tax.

Vehicle	Net yield 2026	Rate certainty	5-yr after-tax $100K result
HYSA	~2.52%	None	$113,250
VMFXX (in brokerage)	~3.29%	None	$117,500
5-yr MYGA @ 5.65%	5.65% gross deferred	Full 5 years locked	$131,636

Related research

HYSA vs Treasury Bills - the related "buy the Treasuries directly" comparison
HYSA vs MYGA
Best HYSA Rates 2026
CD Reviews

Bottom line

HYSA is the right default for most savers - FDIC protection, single login, simple tax reporting. MMF (VMFXX, SPAXX, SWVXX) wins by 60-90 bps net for brokerage-comfortable savers, especially in high-state-tax states. Both lose to a 5-yr MYGA for 3+ year money by 200-300+ bps after tax. Use the right tool for the right time horizon.

About Hans Goldstein: Independent retirement income specialist. CA Life License #4163961. NPN #20602398. Reviews 30+ annuity carriers and the leading bank HYSAs. Hans does NOT earn commission on HYSAs or CDs - these reviews are written for the same risk-averse savers who often end up as MYGA buyers when they need 3+ year money. Phone: 213-414-2808. Email: hans@goldsteinco.net.

Frequently asked questions

What is a money market fund?

A mutual fund that invests in short-term, high-quality debt securities (Treasury bills, commercial paper, repurchase agreements). Designed to maintain a $1.00 net asset value while paying current short-term interest rates.

Is a money market fund FDIC insured?

No. MMFs are securities, not bank deposits. They're held at a brokerage and have SIPC coverage for fraud/brokerage failure (up to $500K including $250K cash) but NOT for investment loss.

Can a money market fund 'break the buck'?

Yes, but it's rare. The Reserve Primary Fund broke the buck in 2008 after Lehman defaulted on commercial paper - investors received ~99 cents on the dollar. Reforms since then (2010, 2014, 2023) make this extremely unlikely for government MMFs but possible in stress events.

What's the difference between VMFXX, SPAXX, and SWVXX?

All three are government money market funds at Vanguard, Fidelity, and Schwab respectively. Similar yields (5.10-5.25% in 2026), similar credit quality (Treasuries + repo). Vanguard's VMFXX has the lowest expense ratio (~0.11%), edging the others on net yield.

Why does VMFXX yield more than HYSA?

Three reasons: (1) MMFs hold direct Treasury exposure - banks pay HYSA rates 50-100 bps below the Fed funds rate; (2) MMFs have lower regulatory capital requirements than banks; (3) the yield is gross of expense ratio (~0.10%) but still net higher than HYSA.

Are MMF dividends taxed the same as HYSA interest?

Federally, yes - both are ordinary income. State tax differs: government MMFs (Treasury-heavy) typically have a portion exempt from state income tax. Check the fund's annual statement of percentage of income from Treasury obligations.

Should I hold a MMF in a brokerage instead of a HYSA?

If you already have a brokerage account, often yes - higher yield, often partial state tax exemption. If you don't, opening a brokerage just for the MMF adds operational complexity that may not justify 30-50 bps.

Can a HYSA replace a MMF entirely?

For simplicity, yes - and for ordinary households, an HYSA is the right default. MMFs make more sense for savers already managing a brokerage account who want every basis point of yield + Treasury state-tax benefit.

Run the MYGA vs HYSA math for your situation

Independent. Licensed. No carrier captive.

HYSAs are the right home for 1-12 months of cash. For 3+ year money, a MYGA typically pays 50-120 bps more and defers tax — a combo that quietly adds 15-25% to your effective yield in a high bracket. Worth 15 minutes to run your real numbers.

Drop your info — within 24 hours you'll get a written side-by-side: your current HYSA yield (after tax) vs. the top MYGAs available for your state today.

Hans Goldstein - 213-414-2808 - NPN 20602398, independent licensed insurance producer appointed with multiple A-rated carriers

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Disclosure

This review reflects publicly available product materials and approximate rates as of the date stated above. HYSA APYs are variable and change frequently - confirm current values directly with the bank before opening an account. FDIC insurance covers up to $250,000 per depositor, per insured bank, per ownership category. MYGA rates referenced are illustrative top-of-market quotes as of 2026 and depend on state, carrier appointment, and product approval; not all MYGAs are available in every state. This article is general information for educational purposes; it is not a personalized recommendation, solicitation, or offer of any specific product. Hans Goldstein is an independent licensed insurance producer (NPN 20602398) appointed with multiple A-rated carriers across the annuity market; Hans is not a banking representative and does not earn compensation on HYSA or CD products. Tax discussion reflects federal law as of 2026 and is subject to change. State tax treatment varies. Always read the actual bank disclosure and consult a licensed advisor or CPA before reallocating retirement-bound funds.