Small-cap stocks are relative to large-cap stocks. Large-cap stock: usually refers to the shares of listed companies with a large number of tradable shares. On the contrary, small-cap stocks are a small number of tradable shares of listed companies.

Mid-cap stocks refer to a class of stocks whose market value is smaller than blue-chip stocks or large-cap stocks, but higher than small-cap stocks. There is no clear standard to define the circulation scope of mid-cap stocks, and the standards of mid-cap stocks in different markets and different periods are different. Taking the current A-share market as an example, it is empirically believed that all stocks with a circulating market value of10-10 billion yuan can be regarded as mid-cap stocks.