Mumbai: Weak stock markets erased Rs 46,856.84 crore (USD 10.6 billion) from the combined market capitalisation (M-cap) of six of India's top 10 firms last week, with RIL taking the biggest hit.

The 30- share Bombay Stock Exchange benchmark index, Sensex, lost 525 points to end the week at 18,197.20.The market cap of Reliance Industries Ltd (RIL) dropped by Rs 15,015.79 crore to Rs 2,71,011.33 crore during the week. Its shares fell by over 5 per cent to close at Rs 827.70. The valuation of state-owned oil & gas major ONGC fell by Rs 9,496.58 crore to Rs 2,29,842.97 crore.

Two of the country's top lenders, SBI and ICICI Bank together shed Rs 13,169.59 crore. The M-cap of SBI fell to Rs 1, 48,714.66 crore, while that of ICICI Bank to Rs 1, 19,567.48 crore.

India's largest power producer NTPC witnessed a dip of Rs 5,813.05 crore from its M-cap, which fell to Rs 1,45,367.46 crore. Infosys Technologies, the country's second largest software exporter, saw its market worth slip by Rs 3,361.83 crore to Rs 1,58,864.12 crore.

In contrast to these six firms, Coal India, TCS, Bharti Airtel and ITC saw gain in their M-cap. Coal India saw its M-cap advancing by Rs 12,032.67 crore to Rs 2,45,043.19 crore, while Bharti Airtel added Rs 9,892.54 crore to its market valuation which stood at Rs 1,65,951.62 crore. Diversified business firm ITC's M-cap surged by Rs 853.67 crore to Rs 1,61,409.59 crore and the country's largest software exporter TCS added Rs 342.51 crore to its valuation which reached Rs 2,22,034.55 crore.