Traders are winning big on their short positions against Chipotle, according to S3 Partners. : A day after Greenlight Capital's David Einhorn lamented over his losing in his short positions against Amazon and Tesla, some hedge fund investors are winning big from their bearish bets on Chipotle. Shorting is a trading strategy where investors borrow and sell shares in hopes of buying them back at a profit after a drop. This kind of trading is mostly done by sophisticated hedge funds.