Placebo: Pre‐Trend Leads
Coefficients at t = –3 and t = –2 (ref = t – 1)
Horizon	Estimate (β̂)	Std. Error	p-value
Lead t–3	161.47	130.67	0.222
Lead t–2	73.55	60.48	0.230
‡ Standard errors clustered by firm.