Shares of listed Tata Group companies lost about $3.2 billion in combined market value on Friday after Tata Sons' board voted 4-1 to give Chairman Natarajan Chandrasekaran another five-year term and move toward complying with Reserve Bank of India rules that could require a public listing. Tata Trusts, which owns 66% of Tata Sons, opposed both decisions, called the reappointment illegal under the company's articles and said the listing could dilute its influence. Chandrasekaran's reappointment as a director remains subject to shareholder approval at an annual general meeting that must be reconvened by December 31. By noon Friday, 302.22 billion rupees ($3.16 billion) had been erased from the listed companies' combined market value, with Tata Chemicals down 9.57% and Tata Consultancy Services down 2.98%.