FZDXX yield: 3.76% as filed, and what it keeps after tax

What the filings say about FZDXX

FZDXX is the premium share class of Fidelity Money Market Fund, the same prime portfolio as SPRXX with a lower expense rate. The filing lists a minimum initial investment of $100,000 and $116.0 billion in the class, far more than the $11.3 billion in SPRXX: most of the fund’s money sits in this class. The filed 7-day yield was 3.76%, against 3.64% for SPRXX on the same day, a gap of 12 basis points. On $100,000 that is about $120 a year before tax. Everything else is shared: the portfolio, the rules on liquidity fees for retail prime funds, and the low share of U.S. obligations, 9% at the last month end. That last point decides the after-tax result in a high-tax state, where FZDXX competes with Treasury funds that pay a little less but keep their state exemption.

FZDXX 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 FZDXX held on October 31, 2026

Share of the portfolio in U.S. government debt whose interest states cannot tax: 9.1%. 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.

FZDXX 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 9% above is the part the calculator treats as tax-free. FZDXX fell below half at one or more quarter ends in the data, so residents of the three states pay state tax on the whole dividend for the year. 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.

FZDXX at a glance

Where FZDXX 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 FZDXX 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 $262 a year more than FZDXX 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 FZDXX

Quarter-end shares of U.S. obligations were 36.6% and 14.1%, below 50% in September, so residents of California, Connecticut and New York pay state tax on the whole dividend.