Money market fund yields after tax, from the funds’ own reports

What this table shows that a yield list does not

Most lists of money market fund yields stop at the 7-day yield, the number fund companies put at the top of their pages. It is the right number to start with and the wrong one to finish with, because two funds with the same yield can leave very different amounts after tax. A Treasury fund’s dividend escapes state income tax; a prime fund’s does not; a government fund sits in between, and in California, Connecticut and New York it can fall on either side of a line drawn at 50% of its assets. The table above takes the yield each fund reported to the Securities and Exchange Commission, the holdings it reported on the same form, and the federal and state tax rates that apply to your income, and ranks the 283 retail share classes by what they leave you. Change the state and the order changes. On the filings for October 2026, the fund with the highest yield before tax, FLGXX at 4.04%, ranked 57 for a Californian with $120,000 of taxable income.

Why the yield is not what you keep

A money market fund pays its income as dividends, and those dividends are taxed as ordinary income at your federal rate, plus the 3.8% net investment income tax above $200,000 of income for a single filer and $250,000 for a joint return. That part is the same for every taxable fund. The state part is where funds differ. Federal law forbids states to tax interest on obligations of the United States, and the same protection covers the debt of a few agencies created by Congress, among them the Federal Home Loan Banks, the Farm Credit Banks and the Tennessee Valley Authority. It does not cover Fannie Mae and Freddie Mac, and it does not cover repurchase agreements, even when the collateral is Treasuries, because the interest is paid by the bank or dealer that borrowed, not by the government.

So the share of a dividend that a state cannot tax depends on what the fund held. Vanguard Federal (VMFXX), Vanguard’s largest money market fund, held 74% of its portfolio in exempt obligations at the end of October 2026; Vanguard Treasury (VUSXX) held 100%; Schwab Prime Advantage (SWVXX), a prime fund, held 1%. For a single Californian at $120,000, those differences turn VMFXX’s 3.88% into 2.85% after tax, VUSXX’s 3.89% into 2.96%, and SWVXX’s 3.77% into 2.51%. In Texas, with no state income tax, the same three give 2.95%, 2.96% and 2.87%, and the prime fund comes out ahead.

The 50% line: 92 of 221 government and Treasury classes miss it

California, Connecticut and New York add a condition. A fund’s dividends from U.S. obligations are exempt in those states only if, at the close of each quarter of the fund’s tax year, at least half of its assets were in such obligations. Miss the line at one quarter end and the whole dividend for the year is taxable in those states, not just the part from repo or agency paper. The holdings in the Form N-MFP reports let anyone check the line. At the June 30 and September 30 quarter ends in the data, 92 of the 221 retail government and Treasury share classes here held less than 50% in Treasuries and exempt agency debt at least once. Some carry the word Treasury in their name: Schwab Treasury Obligations (SNOXX) held most of its money in Treasury repo and stayed below the line at both quarter ends. The 50% rule guide explains the test and shows how to read it from a filing.

Other states take a simpler route. New Jersey, Pennsylvania and Illinois exempt the share of dividends earned on federal obligations, whatever the fund’s mix, and New Jersey does so even for funds that miss its separate 80% rule for qualified investment funds. Nine states have no tax on interest and dividends at all. The comparator applies the rule of the state you choose; for states whose rules this site has not read, it asks for your rate and assumes the federal share is exempt, and says so.

What the averages hide

The spread inside each type is wider than the gap between types. Government funds ranged from 2.58% to 4.04%, and most of that range is cost: the filings give each fund’s gross yield and each class’s net yield for the same day, so the difference is what the class pays in expenses. The cheapest classes give up a few hundredths of a point; 84 classes give up more than half a point, and the most expensive 1.45%, about $1,450 a year on $100,000. Prime funds earn a little more on their holdings because they lend to banks and companies, but after expenses their average sits close to the government average, and their dividends carry almost no state exemption. Municipal funds yield less on paper, about 1.96% on average, because their dividends are free of federal tax; their yields also move more from week to week than any other type.

Each fund page on this site shows the daily filed yield since June 1, 2026, the holdings on the last report, the quarter-end test, the expense drag and the fund’s rank after tax in three states. The comparison pages put two funds, or a fund and a savings account, side by side in one calculator.

Where the numbers come from

Every money market fund registered in the United States files a Form N-MFP report each month with the Securities and Exchange Commission, within five business days after month end. The report lists every security the fund held, the fund’s weighted average maturity and life, its assets by share class, and the 7-day net yield of each class for every business day of the month. The Commission publishes these reports as filed and also releases them as monthly data sets. This site reads both: the data sets for June to September and the individual reports filed from November 3, 2026 to November 6, 2026 for October 2026, 283 share classes and 165 funds in all after leaving out classes with a minimum above $100,000, institutional prime and tax-exempt classes, and classes under $50 million.

Two consequences follow. The yields here are not today’s: they are the last business day of the reported month, and by the time the next report is filed they are about five weeks old. And they are as filed: if a fund later amends a report, the change appears at the next update. The figures are downloaded and the site rebuilt by hand each month; there is no live feed. The data and method page describes each step, the classification of holdings, and where the estimate from holdings and a fund’s year-end tax letter can differ.

How the after-tax yield is worked out

For each share class the comparator takes the filed 7-day yield and your amount to get a year of dividends at that yield. It applies your federal marginal rate from the 2026 brackets of IRS Revenue Procedure 2025-32, adds the net investment income tax when your income is above the threshold, and then the state rate from your state’s 2025 schedule. The state part is applied only to the share of the dividend that is not exempt: the holdings estimate of U.S. obligations, or the full dividend if your state applies the 50% test and the fund missed it. Municipal funds skip the federal tax, and single-state municipal funds skip the state tax in their own state. The result is a rate, not a promise: yields change every day and your actual tax depends on your whole return.

Money funds, savings accounts and Treasury bills

A high-yield savings account is a bank deposit, insured by the FDIC, and its interest is taxed by your state in full. A Treasury bill bought directly pays interest that no state can tax, and you hold it to a fixed date. A money market fund sits between: its share price is held at $1.00, it can be sold any business day, and part of its dividend may escape state tax. The savings comparison and the Treasury bill comparison run the numbers for your state.

Sources

Fund yields and holdings come from SEC filings, and every tax rule and rate from the IRS, state tax agency or statute listed here, each read on November 7, 2026.

• Securities and Exchange Commission, Form N-MFP data sets (monthly, as filed)
• Securities and Exchange Commission, daily index of filings (Form N-MFP3 reports for the latest month-end)
• 17 CFR 270.2a-7, money market funds (rule 2a-7)
• IRS Revenue Procedure 2025-32, 2026 tax rate tables
• IRS Topic no. 559, Net investment income tax
• California Franchise Tax Board, 2025 Schedule CA (540) instructions: funds with 50% of assets in U.S. or California obligations
• California Franchise Tax Board, 2025 California tax rate schedules
• New York State Department of Taxation and Finance, 2025 Form IT-201 instructions (line 28, rate schedules)
• Connecticut Department of Revenue Services, Policy Statement 92(3) on exempt dividends of qualifying funds
• Connecticut General Assembly, Office of Legislative Research, report 2026-R-0057 (2025 brackets of seven states)
• New Jersey Division of Taxation, GIT-5 Exempt Obligations (January 2026)
• New Jersey Division of Taxation, 2025 NJ-1040 instructions and tax rate schedules
• Pennsylvania Department of Revenue, Personal Income Tax Guide: Dividends
• Illinois Department of Revenue, Publication 101, Income Exempt from Tax
• Illinois Department of Revenue, income tax rates
• U.S. Department of the Treasury, daily Treasury bill rates 2026
• 12 U.S.C. 1433, Federal Home Loan Bank obligations and state taxation

Fund data: Securities and Exchange Commission, Form N-MFP, as filed; public information. This site is not affiliated with the Commission or with any fund company. Fund names and tickers belong to their owners and are used only to identify the funds. Total assets of the share classes in the table: $2,767.3 billion.