On Feb. 21, 2018, August Troendle, an Ohio billionaire, made a remarkably well-timed stock trade. He sold $1.1 million worth of shares of Syneos Health the day before a management shake-up caused the company’s stock to plunge 16%. It was the largest one-day drop that year for Syneos’ share price.

The company was one Troendle knew well. He is the CEO of Medpace, one of Syneos’ chief competitors in a niche industry. Both Syneos and Medpace handle clinical trials for biopharma companies, and that year they had jointly launched a trade association for companies in the field.