Five of the top 10 most valued firms together lost Rs 86,447.12 crore in market valuation last week, with Infosys, Tata Consultancy Services and State Bank of India taking the biggest hit. Last week, the BSE benchmark fell 462.8 points or 0.79 per cent. While Reliance Industries Limited, Tata Consultancy Services (TCS), HDFC Bank, Infosys and State Bank of India suffered erosion from their valuation, ICICI Bank, Hindustan Unilever Limited, ITC, HDFC and Bharti Airtel posted gains.