The combined market capitalisation of India's top 10 most-valued companies declined by ₹4.95 lakh crore in the week ended December 20. Tata Consultancy Services (TCS) and Reliance Industries took the biggest hit, with their m-cap declining by ₹1.1 lakh crore and ₹91,140 crore, respectively. Sensex dipped by nearly 4,100 points in the week.