Hi all, I'm working with a prop firm and sent a message to the risk dept. to check on whether they would allow me to open call side positions and immediately close them synthetically via puts (boxes) to lock the interest rate without incurring an interest rate penalty (they just extend me margin via SPAN, and I don't have access to the cash balances or anything like that.) They said sure. I don't see a line on my statements for interest rate charges, and the options themselves have a net credit to carry the position. My question is, surely I can't just lever up a bazillion times and put on a million boxes, right? Someone has to put that money up, and I can't seem to figure out who's putting it up, and who is paying the interest on it. As long as it's not ME, I'm happy, but I've never run a prop firm (just worked for one) so not sure what party is responsible for what in terms of loans and cash flow. Thoughts?