Etfs can't be short, that is, buy down. There is no short-selling mechanism in China, and some ETFs with "R" or "financing" funds can be used for securities lending. However, securities lending requires investors to have a capital requirement of 500 thousand, which means that ETF will fall, so they borrow securities from securities companies at a high level and sell them. When the stock price really falls, investors buy at a low level and return it to the securities company.

ETF fund is a kind of "passively managed" index fund, which tracks and replicates the index and rises and falls with the index. At present, there are many ETF funds in the market, including the common SSE 50ETF, CSI 300ETF, CSI 500ETF, GEM ETF, brokerage ETF, and dual-creation ETF.