IndiGo's co-promoter Rakesh Gangwal on Friday resigned from the board of directors of parent company InterGlobe Aviation, stating that he will gradually reduce the equity stake in the airline over the next five years.

Gangwal and his related entities own around 37 per cent stake in this company. Rahul Bhatia and his related entities own around 38 per cent in InterGlobe Aviation.

"I have been a long-term shareholder in the company for more than 15 years and it's only natural to someday think about diversifying one's holdings," Gangwal said in his letter to the board members.

"Accordingly, my current intention is to slowly reduce my equity stake in the company over the next five plus years," he added.