I am holding shares of Reliance Nippon AMC in my portfolio. What happens to my shares now since Reliance is selling out?

For you as investor it does not make much of a difference. Both Reliance Capital and Nippon held a little over 42% stake each and now the entire promoter stake will be held by Nippon. You may be aware that Nippon is one of the largest financial services conglomerate in the world and operates out of Japan. It is a strong institution with solid credentials. You do not have to really worry about your investment.