The 30-share BSE Sensex declined 187.90 points, or 0.24%, to settle at 77,966.35, with its 21 constituents ending lower, eight with gains and one unchanged. During the day, it tumbled 656.32 points, or 0.83%, to 77,497.93, but recovered some of the losses in the closing session. Mr. Chandrasekaran, 63, has spent 40 years with the Tata Group, which includes his stint as TCS CEO from 2009 to 2017. Among Sensex shares, Mahindra & Mahindra, Tata Steel, Larsen & Toubro, Eternal and Infosys were the major losers. Tata Group stocks came under pressure following the Chairman's exit, contributing to the underperformance of large-cap stocks relative to the broader market, Mr. Nair added.