I shorted the equity directly. The main costs are: - Transaction and Margin costs (those are generally 1 cent per share per side, roughly .06%) - Borr

I shorted the equity directly. The main costs are: - Transaction and Margin costs (those are generally 1 cent per share per side, roughly .06%) - Borrow costs (For that trade it was 30% annualized. I held it for 6 days so its .7%) So the cost to the trade was .76%. The gross return (since you calculate returns relative to the starting point) is (31.5 - 27) / 31.6 = 14.28% and the net return is 13.53% Note that I didnt short as much as I could have -- obviously the return would be higher if I borrowed extra money to short.