Table 8.

Regression results of firm heterogeneity.

Variables	(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
	Environmental investment level		Enterprise size		Industry classification		Nature of ownership
	High environmental investment	Low investment in environmental protection	Large companies	Small and medium-sized enterprises	Manufacturing	Non-manufacturing	State-owned enterprises	Non-state owned enterprises
Dig	0.038***	0.026*	0.058***	0.027*	0.035***	0.071**	0.049***	0.034***
	(3.85)	(1.79)	(4.74)	(1.96)	(4.37)	(2.18)	(2.86)	(3.81)
Size	10.504***	9.945***			9.527***	16.325***	12.220***	9.986***
	(18.68)	(19.84)			(25.78)	(18.04)	(23.54)	(23.31)
Lev	0.263***	0.393***	0.281***	0.788***	0.414***	− 0.462**	0.0720	0.490***
	(3.52)	(5.06)	(3.23)	(10.36)	(8.49)	(− 2.39)	(0.75)	(8.45)
Age	− 0.105	0.0140	0.170	0.181	− 0.0780	0.567**	0.017	− 0.118
	(− 1.03)	(0.10)	(1.20)	(1.36)	(− 1.00)	(1.97)	(0.09)	(− 1.37)
Shrcr1	− 0.000	− 0.002	0.002*	− 0.005***	0.001	0.004	− 0.001	0.001
	(− 0.24)	(− 1.33)	(1.92)	(− 2.82)	(1.58)	(1.07)	(− 0.40)	(1.25)
Board	0.046	− 0.131	0.064	− 0.084	− 0.029	0.001	− 0.001	− 0.024
	(0.71)	(− 1.51)	(0.82)	(− 0.92)	(− 0.57)	(0.01)	(− 0.01)	(− 0.37)
Independent	− 0.309*	− 0.361	− 0.195	− 0.588**	− 0.271*	0.924*	− 0.058	− 0.297
	(− 1.66)	(− 1.40)	(− 0.94)	(− 2.13)	(− 1.87)	(1.81)	(− 0.24)	(− 1.57)
Roa	2.986***	1.817***	2.252***	2.437***	2.477***	1.915***	2.522***	2.446***
	(18.14)	(11.70)	(14.91)	(16.59)	(27.05)	(4.08)	(12.85)	(22.61)
Year	Control	Control	Control	Control	Control	Control	Control	Control
Firm	Control	Control	Control	Control	Control	Control	Control	Control
_cons	− 23.281***	− 21.361***	7.177***	7.966***	− 20.274***	− 43.039***	− 27.754***	− 21.584***
	(− 12.72)	(− 14.11)	(6.68)	(16.77)	(− 18.36)	(− 13.54)	(− 16.24)	(− 16.69)
N	1411	1339	1351	1399	2392	358	980	1770
R2	0.961	0.938	0.928	0.894	0.957	0.958	0.957	0.949

T-statistics are shown in parentheses. ⁎⁎⁎, ⁎⁎ and * indicate 1%, 5% and 10% respectively.