The quoted rates
Dated snapshot from the 2026-09-06 data review. Each product carries its own source date. Confirm a new quote with the issuer if the live calculator has excluded a stale rate.
| Product | Quoted rate | Rate date | Source |
|---|---|---|---|
| SPAXX | 3.34% 7-day yield | 2026-09-04 | Issuer ↗ |
| FDLXX | 3.38% 7-day yield | 2026-09-04 | Issuer ↗ |
A worked example
Illustration using the 2026-09-06 data review: $50,000 for 12 months, 24% federal tax, 5% state tax in California, no local tax or NIIT, and monthly reinvestment for funds. The example HYSA is 3.5% APY and keeps $1,242.50 after tax. Fund exemptions use 2025 information as a proxy.
| Product | Projected gross income | After taxes and fees |
|---|---|---|
| SPAXX | $1,695.80 | $1,204.02 |
| FDLXX | $1,716.43 | $1,303.34 |
These are dated examples at constant rates, not current recommendations. Ranges are mathematical limits, not likely outcomes. Change the inputs below for your situation.
The difference is in the income source
SPAXX is Fidelity’s Government Money Market Fund. FDLXX is its Treasury Only Money Market Fund. Their names do not tell you the exact state-tax treatment: the issuer’s annual tax supplement does. Both are mutual funds, and neither is FDIC insured.
A California example
The worked example uses the dated yields above, $50,000 held for one year, a 24% federal rate and a 5% state rate. The result reflects both the yield difference and the modeled state exemption. Enter your own rates below to see the dollar difference. This is a constant-rate projection, not a forecast of next year’s yield.
The California, Connecticut and New York exception
Fidelity reports that 50.90% of SPAXX’s 2025 income came from eligible U.S. government securities, but flags it as failing the requirements for these three states. The calculator therefore applies no SPAXX state exemption there. FDLXX’s 98.67% government-income figure qualifies under the issuer’s supplement. Elsewhere we use the issuer’s eligible government-income fraction as the estimate; confirm how it applies to your return.
Before moving cash
These fund pages show no initial minimum and no transaction fee at Fidelity. A purchase is still subject to account eligibility and the fund prospectus. Do not assume every money market fund works as an automatic sweep or can be liquidated on the same schedule. The current tax-year percentages will be finalized after year-end.
The calculator ranks only products with a complete tax estimate under your inputs. It does not choose investments for you or guarantee future income. Read the methodology and source documents.