Reverse ETF, also known as short ETF or short ETF, is a transactional open index fund that uses leveraged investment tools such as stock index futures and swap contracts to track the return of the target index at a certain multiple (such as-1 times, -2 times or even -3 times) every day. When the return of the target index changes by 1%, the change of the fund net value reaches-1%, -2% or -3% as agreed in the contract.