Just curious on haircut for hedge funds. As a market maker in options, firms are required to post margin to roughly cover moves in your portfolio >< 15% in the market and also $25 per contract. This is for a medium sized firm making markets under a large BD platform. What are the costs for a large scale, multi $B hedge fund and can they use assets invested elsewhere such as long equity positions, other derivatives and fixed income holdings as collateral? thx