SPAXX yield: 3.55% as filed, and what it keeps after tax

What the filings say about SPAXX

Fidelity Government Money Market Fund is, by assets, the largest share class in this data: $427.5 billion at the end of the reported month. Its filed 7-day yield was 3.55%, while the gross yield of the same portfolio was 3.97%, which means about 0.42% went to expenses, the widest gap of the three big Fidelity government and Treasury funds. That gap is the first thing to know about SPAXX. The second is its maturity profile: a weighted average life of 116 days, the average time until its holdings are paid back in full (the legal limit is 120), because the fund holds floating-rate agency notes that reset their rate often but are repaid late. Because those notes reset their rate often, its other measure, the average time until holdings repay or reset their rate, is only 39 days. The third is state tax. The quarter-end share of U.S. obligations was 61.0% in June and 67.0% in September, so the fund passed the 50% test of California, Connecticut and New York at both dates, but by a margin that has been thinner than at Vanguard’s federal fund.

SPAXX 7-day yield as filed, June 1, 2026 to October 29, 2026

A fund reports these yields once a month, within five business days of month end. Between two reports the figure here ages: by the time the October 2026 report is replaced, it is up to five weeks old. The fund’s own site shows today’s figure.

What SPAXX held on October 31, 2026

Share of the portfolio in U.S. government debt whose interest states cannot tax: 71.1%. This is the figure the calculator above uses as the state-tax-free part of the dividend. It is an estimate from the holdings on one day; the fund’s year-end tax statement gives the share of the year’s dividends, which is the figure for a tax return.

SPAXX and the 50% quarter-end test

In California, Connecticut and New York, the part of a dividend earned on U.S. government debt is state-tax-free only if the fund kept at least half its money in that debt at every quarter end. These quarter-end figures only decide pass or fail; the 71% above is the part the calculator treats as tax-free. SPAXX held at least half its assets in U.S. government debt at every quarter end in the data, so it passes. The law looks at the close of each quarter of the fund’s own tax year, which is not always the calendar quarter; calendar quarter-end reports are a close proxy, and the fund’s year-end letter says whether it qualified. How the rule works.

SPAXX at a glance

Where SPAXX ranks after tax

Among the 283 share classes in the data, for a single filer with $120,000 of taxable income and $50,000 in the fund:

The rank compares SPAXX with every other fund for a resident of that state. In a state with no income tax, such as Texas, funds whose dividends are taxed by states catch up, so the rank can be lower even though you keep more. In California, the fund ranked first kept $215 a year more than SPAXX on $50,000.

A rank of past yields, not a recommendation, and this site does not say which fund to hold. Moving cash to another fund can involve a minimum or a fee set by your brokerage. Rank every fund for your situation.

What to watch in SPAXX

Over the months on file SPAXX moved from 3.28% on June 1, 2026 to 3.55% on October 29, 2026. A buyer comparing it with FDRXX, the same kind of fund with lower expenses, will find the difference in the filed yields: 3.63% for FDRXX on its last reported day.