jayc, I think I see what you are talking about on my accounts. I have the VG Admiral Treasury MM fund and the VG Federal Money Market Fund. I tried buying more than $10,000 in each of these funds, and it does not allow me to do so, stating that there is a $10,000 purchase limit per fund per day.
The solution is to open the "VG Prime Money Market fund" and you can make unlimited purchases in that fund. It yields more than the other MM funds anyway (by a few basis points).
Another thing to point out, and something that took me a while to wrap my head around. Vanguard doesn't have a "sweep" account in their mutual fund accounts. There are only specific money market funds that are basically cash accounts. But you have to think of them as just another mutual fund in your account. When you sell something and put the proceeds into your cash account, you are actually "exchanging" shares of the fund you are selling for shares of the money market fund you are putting the sales proceeds into. It's a little complicated since it is different from how most other brokerage accounts do it.
