Have a few questions about margin lending, as I'm sure some people here use margin. Firstly, does it act as a 'line of credit', so to speak, as a credit-card does? Or is it a straight-up lump sum debt which you then pay interest on, no matter how much you use to buy shares? Also, noticed that the rates are quite high, just looking at comsec it is about 10% (although I believe IB has low rates). Doesn't this make it unattractive for use in long-term investing (as the comsec 'how it works' example depicted), and rather makes it suited for short-term, day-trade type usage (assuming that it is a 'line-of-credit')?