By Senad Karaahmetovic

Moderna (NASDAQ:) CEO Stéphane Bancel announced his plan to donate to charity all of the after-tax proceeds of the original stock options he received upon joining the biotechnology company in 2013.

It is estimated that the donation will amount to approximately $355million, assuming stock prices of around $140/share and $280 million tax payments.

Bancel who was granted the initial stock option grant in 2013 (which is due to expire August 22,2033), stated that he had never exercised any stock options since joining the company eleven years ago.

He added that he offloaded Moderna stock under 10b5-1 plans and gifted the shares to charity, all of which were purchased using his family’s savings before Moderna went public.

Bancel said the stock option “will expire and be worthless” if not exercised now and it presents an opportunity “to create a positive change in the world.”

In an effort to prevent a high number of shares from flooding the market at once and potentially affecting the company’s stock price, Bancel has set up a 10b5-1 plan through which he plans to exercise 40,000 shares on Wednesday and 40,000 on Thursday each week, starting May 25, until fully exercised.

“My family also has our investment entity OCHA LLC, which, under another 10b5-1 plan, sells 10,000 shares each Thursday. This money is invested in companies that have the potential to positively impact the world. These include healthcare businesses and those who work on combating the negative effects of climate change. The 10b5-1 plan for OCHA LLC is scheduled to run through the end of 2022,” said Bancel in a blog post.

Moderna shares were down almost 1% by pre-open Tuesday