Determinants of Upgrading Trading Firms in the Case of Tianjin——In Order to Tianjin as an Example

Under the reversed pressure mechanism,where raw material price and labor cost increase,RMB continuously appreciates,trade friction gets worse and environment deteriorates,trading firms need to upgrade.Most of previous studies focus on Southern Chinese provinces.However,I emphasize on trading firms in Tianjin and examine the determinants of upgrading trading firms with industrial firms database.The results indicate that total factor productivity,RD,firm size,market power and new product significantly promote upgrading firms,however,expansion in exports have significant depression effect on them.