< noob > I was thinking, say your margin interest rate is 10%. So if you held a position open using margin for an entire year, and you made 10%, you would just break even then. So obviously I'm assuming margin is used for shorter-term trades, right? Also, if you're a day trader using the 4:1 margin, but all your positions are closed by the end of the day, do you have to pay interest on the margin you used for less than a day? Thanks < /noob >