As a popular online word, it refers to the fact that some institutions, funds and large households sell stocks in the stock market, which leads to a sharp drop in the stock market. Leek also means cannon fodder, which means that a thing needs to be explored by pioneers before it can be formed, and this pioneer usually has many failures or meaningless situations, so it is called cannon fodder.
There is also the use of fraud to "cut leeks." I think all fraud can also be called "cutting leeks". For example, the common telecom fraud, such as paying a large sum of money to children and the notary fee of the deposit lawyer, is a mess, which is to use the psychology of those who don't understand this kind of fraud routine to implement fraud.
Cutting leeks is to use information asymmetry to deceive people.