Six of the 10 most valued firms suffered a combined erosion of Rs 1,68,260.37 crore from their market valuation last week, mainly dragged down by IT major TCS amid an overall weak trend in the equity market.

The 30-share BSE benchmark Sensex fell 721.06 points or 1.32 per cent last week.

From the laggards, Tata Consultancy Services (TCS) took the biggest hit as its market valuation tumbled Rs 99,270.07 crore to reach Rs 10,95,355.32 crore. Shares of TCS dropped last week after the company's June quarter earnings failed to meet market expectations.

Another IT behemoth Infosys also suffered an erosion of Rs 35,133.64 crore, taking its valuation to Rs 6,01,900.14 crore.

HDFC Bank's market valuation fell by Rs 18,172.43 crore to Rs 7,57,659.72 crore and that of State Bank of India (SBI) declined by Rs 8,433.76 crore to Rs 4,27,488.90 crore.

The market capitalisation (m-cap) of HDFC dipped by Rs 4,091.62 crore to reach Rs 4,02,121.99 crore and that of ICICI Bank went lower by Rs 3,158.85 crore to Rs 5,22,498.11 crore.

In contrast, the valuation of Hindustan Unilever Ltd (HUL) jumped Rs 17,128.52 crore to Rs 6,03,551.26 crore.

Reliance Industries added Rs 6,801.72 crore, taking its market valuation to Rs 16,24,681.08 crore.

ITC's m-cap climbed Rs 1,318.81 crore to Rs 3,62,327.81 crore and that of Life Insurance Corporation of India (LIC) went higher by Rs 316.25 crore to Rs 4,48,157.71 crore.

In the ranking of top-10 firms, Reliance Industries continued to remain the most valued domestic company, followed by TCS, HDFC Bank, HUL, Infosys, ICICI Bank, LIC, SBI, HDFC and ITC.