Its probly cause you dont have a margin account.Takes 3 days for your money to clear after selling.so if you sold today something you can use it thur am.If you have a cash account then you have to wait bud.TXTM should clear those 4's early..
Yes... you need to open up a margin account which you can do thru E trade or Scottrade.
It doesn't mean you have to buy your stock on margin but what it allows you to do is to turn around and trade the same stock 3 times and you won't have to wait 3 days to clear.
You have to wait 3 days to be able to use your $ again, so let's say you buy today and you sell tomorrow, then you will not be able to use that $ till thursday.