When co-founder Rakesh Gangwal decided to sell shares worth 2,000 crore ($250 million), IndiGo's stock plummeted by nearly 4% in early trade. Following his resignation from the board of directors of the company six months ago, Gangwal has decided to lower his ownership in India's largest airline. 10.8 million shares will be sold in the block deal, with a floor price of $1,850 per share.