Can I day trade in a margin account?

Yes, if your total account equity (including all of your cash and securities) is below $25000, you can day trade up to 3 times within five consecutive business days. Five consecutive business days do not necessarily represent from Monday to Friday, it is back counted five business days from the concurrent day and including the concurrent day. Once your account has 3 day trades within five consecutive business days, your account will be restricted from opening new positions until the next trading day that allows you to day trade again.