The entire point of collateral is to hedge against you not being able to provide the money in two days, when the share actually is exchanged for cash. If, inste

The entire point of collateral is to hedge against you not being able to provide the money in two days, when the share actually is exchanged for cash. If, instead of collateral, you got the cash, capital requirements would be reduced as you would get the money from sales immediately, and wouldn't need to keep a pile of money to collateralize buys while waiting on the income from your sales.