ETF is a kind of portfolio securities that securitizes the index, replicates the underlying index, and builds a tracking index. Investors can buy and sell a package of securities by trading fund shares. Characteristics of ETF: (1)ETF can be used as an open-end fund, which can be purchased and redeemed at any time. (2) convenience and low cost. (3) can invest in a stock industry index, some specific sectors and a basket of diversified stocks.

At present, China's SSE 50ETF option has been officially listed on the Shanghai Stock Exchange. SSE 50ETF option belongs to a narrow sense of stock portfolio, so its options can be regarded as stock options. 983