PE (Private Equity): In a narrow sense, PE mainly refers to private equity investing in mature enterprises that have formed a certain scale and generated stable cash flow. In a broad sense, PE refers to the equity investment covering all stages before the initial public offering of an enterprise, that is, the investment made by the enterprise in each stage of seed stage, initial stage, development stage, expansion stage, maturity stage and Pre-IPO. Mainly can be divided into three types: PE- growth: investment expansion period, mature enterprises; PE-PIPE: investing in listed companies; PE-Buyout: M&A is the main business of many famous private equity firms in Europe and America.