Noel Tata, 69, faced a boardroom battle to prevent Tata Sons from listing on the stock exchange. The Reserve Bank of India ruled that the holding company, which controls the $280bn Tata Group's 26 listed companies, must list. Noel, who chairs the Tata Trusts, argued that listing would irrevocably change the group's character.

He backed his position with a written statement and an opinion from a former chief justice of India, opposing a chairmanship extension for N Chandrasekaran. The board ignored Noel and reappointed Chandra for five years, also deciding to comply with the central bank's listing directive. Tata Trusts called the decision a "legal nullity" because its two board nominees were split. Analysts say a listed Tata Sons could be worth over $120bn, making it India's biggest IPO.

Shareholders are set to vote at an AGM expected by year's end.