Table 3.

Difference-in-difference (DID) estimator, δ3 in the main analysis and robustness test using Year −3 as baseline

Year, t	(1) Main analysis	(2) Robustness test
	First to third closest PS	Fourth to sixth closest PS	Seventh to ninth closest PS
−2	0.027a	0.019	0.025
	(0.013)	(0.013)	(0.013)
−1	0.035b	0.033b	0.042b
	(0.012)	(0.012)	(0.012)
0	0.021	0.006	0.018
	(0.012)	(0.013)	(0.013)
1	0.057b	0.043b	0.051b
	(0.015)	(0.015	(0.016)
2	0.003	0.014	0.002
	(0.025)	(0.022)	(0.028)
3	0.031	0.037	0.049
	(0.027)	(0.029)	(0.026)
4	−0.019	−0.030	−0.017
	(0.036)	(0.038)	(0.037)

Note: cluster robust standard errors in parentheses. Baseline: 3 years before merger approval by the regulator.

^a P < 0.05; ^b P < 0.01.

PS, propensity score.