SPAXX vs VMFXX: the two big cash funds after tax
SPAXX and VMFXX are where Fidelity and Vanguard put the uninvested cash of a brokerage account. Here is what each leaves you after tax, from the yields they reported for October 29, 2026 (SPAXX) and October 30, 2026 (VMFXX). Not investment advice.
Example result
SPAXX after federal and California tax
2.60%
$1,301 a year kept on $1,775 of dividends
| Dividends before tax | $1,775 |
| Federal tax at 24.0% | −$426 |
| State tax at 9.30% $1,263 of the $1,775 is free of California tax | −$48 |
VMFXX after federal and California tax
2.85%
$1,427 a year kept on $1,940 of dividends
VMFXX leaves $126 more a year than SPAXX.
Yields reported by the funds for SPAXX October 29, 2026, VMFXX October 30, 2026; yields change daily. Estimate, not tax or investment advice. Nothing you type leaves your browser. How it is computed
Two default cash funds, one gap that does not close
Most people who own SPAXX or VMFXX did not choose them: they are where cash lands in a Fidelity or a Vanguard brokerage account. That makes the comparison a question about the account, and the filings answer the money part of it. VMFXX reported a 7-day net yield of 3.88% and SPAXX 3.55%. Their gross yields, what the portfolios earned before expenses, were much closer: 3.99% and 3.97%. Most of the gap is therefore cost, not strategy. The portfolios do differ in shape. SPAXX holds more agency repo and longer floating-rate agency notes, which pushed its weighted average life, the average time until holdings are paid back in full, to 116 days against 50 for VMFXX; VMFXX held more Federal Home Loan Bank and Farm Credit debt. Neither difference changes the tax picture much: both funds earned most of their income from obligations that states may not tax, and both cleared the 50% quarter-end test.
The calculator above starts from a single filer in California with $120,000 of taxable income and $50,000 in cash. With those numbers VMFXX leaves 2.85% and SPAXX 2.60%, a difference of $126 a year. Whether that justifies moving an account is a judgment about everything else the account does.
SPAXX and VMFXX side by side
| SPAXX | VMFXX | |
|---|---|---|
| Type | Government | Government |
| 7-day net yield as filed | 3.55% | 3.88% |
| Gross 7-day yield of the fund | 3.97% | 3.99% |
| Expenses taken from the yield (expense drag) | 0.42% | 0.11% |
| State-tax-free part (U.S. government debt), last month end | 71.1% | 73.5% |
| U.S. government debt, June 30, 2026 | 61.0% | 67.9% |
| U.S. government debt, September 30, 2026 | 67.0% | 75.4% |
| Average days until holdings repay or reset their rate (weighted average maturity) | 39 days | 25 days |
| Average days until holdings are paid back in full (weighted average life) | 116 days | 50 days |
| Assets in the share class | $427.5 billion | $374.1 billion |
| Minimum initial investment on file | $1 | $3,000 |
| After tax, California | 2.60% | 2.85% |
| After tax, New York (outside NYC) | 2.64% | 2.89% |
| After tax, Texas | 2.70% | 2.95% |
The after-tax rows use one fixed example, the same in every side-by-side table on this site: a single filer with $120,000 of taxable income, and this site’s estimate of the state-tax-free part. Your own figures go in the calculator above.
Questions about this page
Tap a question to see the answer.
Is VMFXX better than SPAXX?
On the filed figures VMFXX yielded 3.88% and SPAXX 3.55%, mostly because SPAXX keeps more for expenses: about 0.42% of its gross yield against 0.11%. Better for you depends on where your account is and what moving it costs, which this site does not judge.
Which has more state-exempt income, SPAXX or VMFXX?
At the last month end VMFXX held about 74% in Treasuries and exempt agency debt and SPAXX about 71%. Both passed the 50% quarter-end test in June and September. The year-end letters of each company give the share of dividends to use on a return.
Can I hold VMFXX at Fidelity?
Some brokerages let customers buy other companies’ money market funds, sometimes with a transaction fee or a different share class, and some do not. The Form N-MFP filing says nothing about where a fund can be bought; check the brokerage’s fund list and fee schedule.
Other pages
Filings, rules and tax schedules behind this page
Compiled by Radif Partners
Independent publisher of money market fund yield and after-tax calculators built on Form N-MFP filings
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Fund data as filed for 2026, site checked on