Salt-to-software conglomerate Tata group, the country's largest in terms of market wealth, has also taken the biggest hit of over $20 billion in its market valuation since July.

Indian stock market has been under tremendous pressure in recent weeks, primarily due to global economic worries, and its overall valuation has fallen by an estimated $200 billion so far in the current quarter, beginning July 1.

The loss suffered by Ratan Tata-led group accounts for over 10 per cent of the overall loss in the market and is also higher than a cumulative erosion of $15 billion from the stock wealth of two Ambani groups.

While Mukesh Ambani-led Reliance Industries group has lost close to $9.89 billion, the group led by younger Ambani sibling Anil has seen little over $5 billion being eroded from its market wealth in this period.

An analysis of market wealth data of large corporate groups shows that the business houses having suffered significant erosion in their valuation also include Vedanta, Adani, ICICI, Infosys, Wipro and Jindal groups.

On the other hand, the losses have been relatively less for groups like Birla, Mahindra, Bajaj, HDFC and L&T, while that of Sunil Mittal-led Bharti group has actually seen a marginal increase of Rs 19 crore since July 1.

The Indian market's total valuation has fallen from $1.53 trillion (Rs 67,31,000 crore) at the beginning of this quarter to $1.33 trillion (Rs 59,29,250 crore) currently.

The market benchmark Sensex has dropped by over 2,500 points or about 13 per cent in this period.

Among individual groups, Tatas' market wealth has fallen from a little over $100 billion (about Rs 4,48,000 crore) on July 1 to $79.5 billion (about Rs 3,55,000 crore) -- a loss of about Rs 93,000 crore ($21.13 billion) for the group.

During the same period, Mukesh Ambani-led Reliance group's market wealth has plummeted by over Rs 43,000 crore from Rs 2,83,000 crore to Rs 2,40,000 crore.

On the other hand, Anil Ambani group's market value has fallen by over Rs 22,000 crore ($5.03 billion) to about Rs 60,300 crore currently.

Among other major groups, Adani and ICICI groups have lost about Rs 30,000 crore each and IT giant Infosys has seen more than Rs 40,000 crore eroded from its value. The losses are more than Rs 20,000 crore for Anil Agarwal-led Vedanta group, Jindals and Wipro also.

In percentage terms, Anil Ambani group has lost about 27 per cent, while losses are over 20 per cent for Tatas, Adani, Infosys, ICICI, Wipro and Jindals also.

The Mukesh Ambani group's loss is about 15 per cent, while that of Vendata group is 18 per cent.