The combined market valuation of five of the top 10 valued firms eroded by Rs 1,67,936.21 crore last week, with HDFC Bank emerging as the biggest laggard. Last week, the 30-share BSE benchmark fell by 1,144.8 points 1.57 per cent. The NSE and BSE conducted normal trading sessions on January 20. While Reliance Industries, Tata Consultancy Services (TCS), HDFC Bank, Hindustan Unilever and State Bank of India faced erosion in their valuation, ICICI Bank, Infosys, Bharti Airtel, Life Insurance Corporation of India (LIC) and ITC were the gainers in the top-10 pack. The market valuation of HDFC Bank eroded by Rs 1,22,163.07 crore to Rs 11,22,662.76 crore. Shares of HDFC Bank fell for the third day in a row on Friday, tumbling over 12 per cent, as investors deserted the counter after the company's December quarter earnings failed to impress the market. HDFC Bank shares bounced back on Saturday, climbing 0.54 per cent. Reliance Industries valuation fell by Rs 18,199.35 crore to Rs ...