Tax-exempt money market fund

[Ronstar]

I'm thinking of moving cash to a new Vanguard tax-exempt money market fund VMSXX- mainly for emergency cash and a place from which I DCA into other funds. Current cash reserves are at 3.74%, 3.96%, and 2.8% which is 2.5%, 2.65%, and 2.4% after tax. VMSXX is at 3.3%. Is there any reason not to do this?

http://https://personal.vanguard.com/us/FundsSnapshot?FundId=0045&FundIntExt=INT

[Jay_Gatsby]

Don't see any real issues with it.

[Art G]

Long ago I was warned against ever using tax free money market funds. It seems that during the savings and loans debacle of the 80's, the tax free's were the only ones at risk of failing.
I think it's that they have too many remarketed preferreds for yield.