Variables	Descriptions
NROA	Net profit margin on total assets, net profit/ending balance on total assets.
Treated	The dummy variable of "outbreak impact degree" is 1 if the enterprise belongs to the high-impact region, otherwise it is 0.
Period	The dummy variable of "outbreak time" is 1 after the outbreak, or 0 otherwise.
SIZE	The size of an enterprise is measured by the logarithm of its total assets.
LEV	The asset-liability ratio is the total liabilities/total assets measure.
GROWTH	Growth rate of operating income, i.e. (current operating income - previous operating income)/previous operating income.
HF10	The Herfindahl index 10, or the share held by the top-10 shareholders.
TR	Trade receivable turnover/1000, trade receivable turnover=revenue/average trade receivable balance.
INDUSTRY	Used to control industry fixed effect.
YEAR	Used to control the fixed effect of year.