As the billionaire Mistry clan and the Tata conglomerate head for a bitter split, they are already preparing for their next battle: the value of a stake in Tata Sons, which is at the center of India's biggest corporate feud.

MUMBAI - Industrialist Ratan Tata sensationally returned to the helm of India's biggest conglomerate on Monday as Tata Sons dumped Cyrus Mistry as chairman in a shock announcement that stunned analysts.