The announcement sent Pfizer's shares soaring almost 15% on the day.

Bourla sold 132,508 shares at an average price of $41.94 per share, or $5.6 million, according to filings registered with the Securities and Exchange Commission. 

Technically, his stock sale was carried out through a "routine" Rule 10b5-1, a predetermined trading plan that allows company staff to sell their stocks in line with insider trading laws.

But he only adopted the plan on August 19.

I'm sure it was just a coincidence that the announcement was made on the same day as Bourla was scheduled to "pre-plan" sell his stock