PSM-DID: Alternative matching variables.

This table presents the robustness test of PSM-DID by using alternative sets of matching variables. Only coefficients of interest (TREAT×POST) are included in this table. Columns (1) and (2) show the average treatment effects of regressions with firm and merger fixed effects. Columns (3) and (4) report the average treatment effects of regression with firm×merger fixed effect. Standard errors are adjusted for heteroskedasticity and clustered by firm. *, **, and *** indicate significance at the 10%, 5%, and 1% levels, respectively. Standard errors are shown in the parentheses.