Ambani, the country's richest man, his family members and some entities linked to them were penalised by the Securities and Exchange Board of India (SEBI) for not making regulatory disclosures when they collectively raised their shareholding in Reliance by nearly 7% by subscribing to the January 2000 issue.
Reliance Industries did not immediately respond to a request for comment.
Ambani and others "by their failure to make public announcement, deprived the shareholders of their statutory rights/opportunity to exit from the company", the SEBI said in its order.
In January, the regulator fined Reliance 250 million rupees, and Ambani 150 million rupees, for what it said were fraudulent trades while selling a stake in a subsidiary in 2007.
(Reporting by Abhirup Roy; Editing by Pravin Char)
