Resurgent Tata is most valued group, again Tata Elxsi, Tata Steel Long Products, Tata Power, Tata Steel BSL among others have rallied between 15 per cent and 48 per cent in the last month. Synopsis The Tata Group has gained Rs 1.9 lakh crore or 13 per cent in overall market cap in one month and Rs 3.33 lakh crore or 42 per cent during the past year. The Sensex gained 19 per cent last year. Mumbai: Tata Group has regained the top position as the most valuable business conglomerate in India thanks to the rebound in some of the beaten-down shares. The total market capitalisation of all Tata Group companies was Rs 17 lakh crore on Wednesday, followed by HDFC Group at Rs 15.25 lakh crore.