| Type | Variable Name | Variable Definition |
| Dependent variable | UNDERPRICE | UNDERPRICE, the percentage gain of the listed company closing price on the first day against issue price |
| RETURN | RETURN, the percentage gain of closing price one year after the listing against closing price on the first day | |
| Explaining variable | UR_DIRECT | Dummy variable of direct investment and sponsor, when the direct investment department of securities companies to which the sponsor institution of issuer belongs holds shares of issuer t, it is 1, otherwise, it is 0 |
| Control variable | UR_RP | Underwriter’s reputation, it uses the logarithm of domestic securities trader annual IPO underwriting amount from 2012 to 2017 as the underwriter’s reputation and alternative indicator |
| OCF | operating activity cash flow of each stock, operating activity cash flow of each stock in the last year of reporting period | |
| PG | The growth rate of net profit, the growth rate of net profit in the last year of issuer reporting period | |
| LEV | Asset-liability ratio, asset-liability ratio in the last year of issuer reporting period | |
| SIZE | Asset size, Napierian logarithm of total assets in the last year of issuer reporting period | |
| SOE | Dummy variable for ownership nature of the ultimate controller, if ownership nature of the ultimate controller is state-owned, find the value of 1, otherwise, 0 | |
| VC_PE | For issuer there are venture capital institutions and private equity with shares, the dummy variable finds the value of 1, otherwise, 0 | |
| IND | Industry dummy variable, if belonging to the primary industry, find the value of 1; if secondary industry, find the value of 2; if tertiary industry, find the value of 3 | |
| YEAR | Year DUM | |
| INDEX | The corresponding percentage gain of index on the first day of listing | |
| INDEX_YEAR | The corresponding percentage gain of index on the first day of listing in the same term |