You have cash you want to keep safe and earn a little on. Two popular homes for it: SGOV, an ETF that holds short-term Treasury bills, and a money market fund, a mutual fund built to hold a stable $1 price. Both invest in safe, short-term paper. Both pay you roughly whatever short-term rates are at the moment. So the choice is not really about yield. It is about structure, fee, and taxes.
Here is the honest way to decide, and the one factor (your state tax rate) that quietly settles it for a lot of people.
What Each One Actually Is
SGOV is an exchange-traded fund. It holds a rolling basket of 0 to 3 month US Treasury bills, charges 0.09% a year, trades like a stock during market hours, and pays income monthly. Its price floats slightly with interest rates, though for an ultra-short Treasury fund the movement is tiny. You can hold it at any brokerage.
A money market fund is a mutual fund engineered to keep a constant $1 share price. Your balance does not visibly move; you just accrue yield daily. The fee depends on the fund, often in the 0.10% to 0.20% range for the big brokerage default funds. Two flavors matter: government money market funds (like SPAXX, VMFXX, or SNVXX) hold Treasuries and government repurchase agreements and are very safe. Prime money market funds hold short-term corporate paper, pay a touch more, and carry slightly more risk, including the possibility of redemption fees or gates in a crisis. For cash you actually need, stick to government funds.
The Differences That Decide It
| Factor | SGOV (ETF) | Govt money market fund |
|---|---|---|
| Fee | 0.09% per year | Usually 0.10% to 0.20% |
| Share price | Floats slightly | Stable $1 |
| Buy / sell | Trade during market hours, settles next day | Often instant if it is your broker's sweep |
| Idle cash earning | After you buy in | Automatic the moment cash lands (as a sweep) |
| State tax on income | Almost fully exempt (pure T-bills) | Partial. Only the direct-Treasury portion qualifies |
| Where you can hold it | Any brokerage | Often tied to one fund family |
Convenience Goes to the Money Market Fund
If a government money market fund is your brokerage's default settlement (sweep) fund, it is the most frictionless place cash can sit. The moment money lands in your account it starts earning, and you can buy other funds instantly without selling anything first. SGOV makes you place a trade to get in, and when you sell, the cash settles the next business day before you can redeploy it. For an everyday cash bucket you dip into often, that difference is real.
Taxes Go to SGOV, and It Can Be the Bigger Number
This is the part most comparisons skip. Income from US Treasuries is generally exempt from state and local income tax. SGOV holds actual T-bills, so almost all of its income qualifies for that state exemption. A government money market fund holds a mix of Treasuries and repurchase agreements, and the repo income usually does not qualify. So only part of a money market fund's payout is state-tax-exempt, and that share changes year to year.
In a no-income-tax state like Texas or Florida, this does not matter. In a high-tax state like California or New York, it can matter more than the fee. A larger state-tax exemption on SGOV can outweigh a money market fund's slightly different yield or a one or two basis point fee gap. If you live somewhere with a high state income tax, run the after-tax comparison, not the headline yield. The full state-by-state numbers, including Massachusetts, New Jersey, and the nine states where this is moot, are in the SGOV state tax breakdown.
The Short Version
- Both hold safe, short-term government paper and pay roughly the same pre-tax yield.
- A government money market fund used as your sweep is the most convenient: instant earning, instant redeploy.
- SGOV's income is almost fully state-tax-exempt. Money market funds are only partially exempt, because of the repo portion.
- In a high-tax state, SGOV can win after tax. In a no-tax state, convenience usually wins.
- Skip prime money market funds for emergency cash. Government funds and SGOV are the safer lane.
Wondering whether to skip the fund entirely and buy Treasuries yourself? We worked through that in SGOV vs buying T-bills directly. Comparing SGOV specifically to Vanguard's settlement fund? See SGOV vs VMFXX.
Want the matchup against the specific fund your cash is probably already in? We compared SGOV head to head with each of the big four money market funds: SGOV vs SPAXX (Fidelity's default sweep), SGOV vs SWVXX (Schwab's prime fund), SGOV vs VUSXX (Vanguard's Treasury fund), and SGOV vs FDLXX (Fidelity's tax-friendly option). The full set lives on the cash comparisons hub.
Common Questions
Is SGOV better than a money market fund?
It depends on your state tax rate and how often you touch the cash. For everyday cash you move in and out of often, a government money market fund used as your brokerage's sweep is more convenient: it earns the moment cash lands and lets you redeploy instantly. SGOV pulls ahead in two cases: you live in a high state-tax state, where its near-full Treasury exemption can beat a money market fund after tax, or you want a cash holding you can move between brokers. Both hold safe short-term government paper and pay roughly the same pre-tax yield, so the decision is about structure and taxes, not headline yield.
Is SGOV's income exempt from state taxes?
Almost entirely. SGOV holds actual US Treasury bills, and Treasury income is generally exempt from state and local income tax, so nearly all of SGOV's payout qualifies. A government money market fund holds a mix of Treasuries and repurchase agreements, and the repo income usually does not qualify, so only part of its payout is state-tax-exempt. In a high-tax state like California or New York, that larger exemption on SGOV can matter more than a one or two basis point fee difference. In a no-income-tax state like Texas or Florida, it does not matter.
What is the difference between SGOV and a money market fund?
SGOV is an exchange-traded fund that holds 0 to 3 month Treasury bills, charges 0.09% a year, trades like a stock during market hours, and has a share price that floats slightly. A money market fund is a mutual fund engineered to hold a stable $1 share price; the big government funds like SPAXX, VMFXX, and SNVXX charge roughly 0.10% to 0.20% and often double as your broker's cash sweep. Both are safe and pay similar pre-tax yields. The practical differences are convenience, fee, and how the income is taxed at the state level.
Can SGOV be used as a settlement or sweep fund?
No. SGOV requires you to place a buy order to get in, and when you sell, the cash settles the next business day before you can redeploy it. A government money market fund that is your brokerage's default sweep earns the instant cash lands and lets you buy other funds without selling anything first. For an everyday cash bucket you dip into often, that convenience favors the money market fund. SGOV fits better as a deliberate holding, especially in a high state-tax state.
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