Fidelity Government Money Market Fund
The largest money market fund in the United States, and the default cash sweep for millions of brokerage accounts. Money funds hold short government paper and aim to keep a share worth exactly one dollar — a promise that is not a guarantee, and whose failure in 2008 required a Treasury backstop for the whole industry.
- Bought and sold
- SPAXX — at net asset value from the manager, not on an exchange. A money market fund is bought and sold at net asset value with the fund company, not on an exchange. Its ticker is quoted through the Nasdaq mutual-fund quotation service, which distributes daily NAVs rather than trading shares.
- Type
- Money market fund
- Manager
- Fidelity Investments
- Strategy
- Government money market — stable $1.00 share price
- Domicile
- United States
- Size
- $456.9bn — net assets of the whole series, all seven share classes, as reported at 2026-07-31
Share classes of the same fund
Fidelity Government Money Market FundSEC series S000007051 · FIDELITY HEREFORD STREET TRUST
| Class | Ticker | SEC class id |
|---|---|---|
| Fidelity Government Money Market Fund this page | SPAXX | C000019230 |
| Capital Reserves Class | FZAXX | C000154303 |
| Daily Money Class | FZBXX | C000154304 |
| Premium Class | FZCXX | C000154305 |
| Advisor M Class | FZGXX | C000190683 |
| Class K6 | FNBXX | C000198393 |
| Class S | FZSXX | C000232685 |
These are not different funds. They are one portfolio sold on different terms — the same holdings, the same manager, different minimums and fee schedules, and in Vanguard’s case the ETF is itself a share class of the mutual fund. A comparison that treats SPAXX and FZAXX as rivals is comparing a fund with itself.
Series and class identifiers and their names come from the SEC’s Investment Company Series and Class report — the registry that assigns them, not our own naming. Holds short-dated government paper and aims to keep a share worth exactly $1.00 — the stable price it reported to the SEC. That is a target, not a guarantee.
Where the size figure comes from
| Reported | $456.9bn |
| What it counts | net assets of the whole series, all seven share classes |
| As of | 2026-07-31 |
| Source | SEC N-MFP data set |
| Fund LEI | 549300VZUKS6UD4H4866 |
Money market funds file N-MFP monthly rather than N-PORT quarterly, so this figure is both from a different form and more current than the rest of the table.
This counts every share class of the fund, which is what the filing reports. Our earlier figure of $456.9bn was the SPAXX class on its own. Both are true and they are not the same quantity — a fund files for the whole portfolio, while a quote screen shows one class of it.
Approximate reference values from public sources · seed-0.7 · marketcap-1 · 2026-08-30 · not real-time. See data & methodology.
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