From what little I've read on the matter if they're offering you the ability to trade instantly when you send them money, they are allowing you to trade on marg

From what little I've read on the matter if they're offering you the ability to trade instantly when you send them money, they are allowing you to trade on margin. That is to say that the money you've sent them won't actually settle in their account until several days later (depending on their clearing house). Therefore they're actually taking on a loan to allow you to use their services "instantly" - this is entirely transparent to the user.