Originally posted by dr_ma
"Can someone explain to me why the second buy is allowed in this example? I mean, either you have the cash or you don't. If you have the cash, then you should be allowed to buy. If you don't, you shouldn't."
The problem is the three day settlement. If everything settled imediately then you could day trade because you would always have the cash that is shown in your account. The reason you are able to buy a second time is because you don't actually have to pay for your trade on the day you place it. You are allowed to wait the three days for the settlement to happen and then everything pays for itself. Where this whole interpretation falls apart is the following day. Your broker will let you use your $10k the following day even it your trade from the previous day has not settled. This is where it becomes clear to me that this is not about paying for trades or settlement days or freerides, but it is actually about daytrading and keeping as many people from doing it as possible. The people who regulate our industry know very little about capitalism or free markets. This is a perfect display of that fact.