I'd like to share my experience about withdrawing money from Charles Schwab.
I happens that I just withdrew some cash from my Charles Schwab account yesterday. I used wire transfer. The transfer amount was larger than $250K, in one single wire transfer.
I'm pretty sure that Charles Schwab has NO limit on the amount of money you can withdraw, if you use wire transfer. According to Charles Schwab, you can wire transfer as much cash as you have in your account, to another bank, for example to your Band of America account.
I hope this information helps.