money market funds有很大部分是US obligations，這部分可以免州稅吧？

Vanguard settlement fund has 49.37% US obligations, Fidelity is 41.18%.

其他funds也有。

https://investor.vanguard.com/investor-resources-education/taxes/funds-tax-information

Vanguard funds that held U.S. government bonds (i.e., government obligations) (PDF)

https://www.fidelity.com/tax-information/fidelity-mutual-fund-tax-information

2023 Percentage of Income from U.S. Government Securities