Pfizer's chief executive Albert Bourla sold company stock at $41.94 a share for proceeds of more than $5.6 million shortly after it announced the success of its coronavirus vaccine. The shares are set to open Wednesday at $39.20.

His decision to sell shares is legal because it was done under a Securities and Exchange Commission predetermined and approved plan that makes distinction between insider trading and legitimate share sales. The share sale was approved by the Securities and Exchange Commission in August.

But some don't like the sale because the executive was privy to the plan to announce the success of its vaccine. Earlier in the week, Pfizer announced that its drug developed with BioNTech was proven to be 90% effective in treating COVID-19.

The announcement sent the company's stock prices up by as much as 8% from a Friday close of $36.40 a share to a Monday opening of $41.92 per share. It closed at $38.68 a share Tuesday.

Bourla reportedly sold 132,508 Pfizer shares Monday at $41.94 a share. That was 60% of his holdings in the company. Other top executives got a big payday from the stock's rally. Pfizer's executive vice president Sally Susman reportedly also sold 43,662 shares the same day for proceeds of $1.8 million.

Pfizer's data showed no serious safety concerns. If the results hold up, the vaccine could become the prime candidate for worldwide distribution.

The company will request an emergency use authorization from the Food and Drug Administration to immediately begin distribution. It is prepared to supply doses for 15 million to 20 million people by the end of the year.

Pfizer's senior vice president and head of vaccine research Kathrin Jansen said in a statement the creation of the vaccine was a "historical moment." She added that the company achieved something that nobody had ever done and that was to create a vaccine for a pandemic in less than a year.