Answer
Tata Group, India's largest conglomerate, was the major Indian company in which Pallonji Mistry held a significant stake. Mistry's family, the Shapoorji Pallonji Group, was the largest shareholder in Tata Sons, the holding company of the Tata Group, with a controlling interest of over 18%. Mistry's involvement in Tata Group spanned several decades, and he played a key role in shaping the company's strategic direction and growth.