Hedge funds short the stockmarket like retail traders do. They do not borrow shares because it is risky. Steven Cohen and Citadel found out the hard way with their GME and AMC short positions. They borrowed shares of stock. Your risk to the upside is unlimited when you short a stock by borrowing shares. Instead, hedge funds buy put options to short any stock. Risk is limited to cost of the premium. Maximum gain is when the stock they shorted goes to zero. Of course, the stock they shorted does not have to go to zero. A $500 stock that drops to $300 will easily give you windfall profits with your put options.