Variable symbol

Variable interpretation

RD

LN (R&D investment/total assets +1)

Pledge_ratio (Pr)

Equity pledge ratio, the ratio of the number of shares pledged by controlling shareholders to the number of shares held

Pledge_dum (Pd)

Dummy variable, the stock pledge of the controlling shareholder in the current year is 1, otherwise 0

Size

Company size, logarithm of total assets

Lev

Financial leverage, total liabilities divided by total assets

Cfo

Cash flow capacity, free cash flow to total assets

Growth

Revenue growth rate

Independ

Independence, the ratio of the number of independent directors to the board of directors

SOE

Dummy variable, state-owned enterprise is 1, otherwise is 0