Subject: Re: Schwab: Problem to invest cash
I don't have the answer to your specific question, but you may have the option of actually purchasing T-bills rather than any fund. 3 months or 6 months or whatever...both of those are yielding over 5.5% right now. Call them and try placing a buy order.
You'll get a great yield, and certainly won't have a problem with liquidity if you want the money before maturity.

Once upon a time I asked Interactive Brokers about this. They said they don't really promote it, and there wasn't (at the time) a way to do it on line, but they said "sure we do it--just call".

Jim