Salt-to-software conglomerate Tata group has suffered a huge erosion of over Rs 25,000 crore in its market valuation within a week, as shares of its companies lost ground amid a sharp sell off in the market.

As a result, the cumulative market value of nearly 30 listed companies of Tata group has fallen below the over Rs 5 trillion mark to Rs 4,85,000 crore (about USD 85 billion).

A week ago, the group's market valuation stood at near Rs 5,10,000 crore (nearly USD 90 billion), shows an analysis of market capitalisation data available with the stock exchanges.
The companies having suffered large erosion in values included Tata Motors, TCS, Tata Steel, Tata Power and Titan Industries, although a few entities like Rallis and Tata Elxi managed to buck the downtrend over the past week.

TCS, the group's most valued entity with a market cap of nearly Rs 2,84,000 crore, lost around Rs 4,000 crore of market wealth, while Tata Motors saw its market worth slip by over Rs 9,000 crore to Rs 88,200 crore.

Titan also lost over Rs 4,500 crore, while the erosion was around Rs 2,000 crore each for Tata Steel and Tata Power.

The cumulative market value of all listed companies in the country has fallen by about Rs 2 lakh crore in this period to close to Rs 64.5 lakh crore.

Shares of the Tata group companies have been among the star performers on the Indian stock market over the last few years. However, shares of many of them have been under pressure in past couple of months amid an overall selling pressure in the market.

While the Indian stock market's overall market capitalisation has actually declined from close to USD 1.4 trillion at the end of 2009-10 fiscal to a little over USD 1 trillion currently, Tatas' market worth has still grown from nearly USD 75 billion to USD 85 billion in this period.

Tatas' market value had even crossed USD 100 billion in 2011 and remained above this mark for quite some time.

However, it later slipped below this milestone amid a downtrend in share prices as also depreciation in the rupee value against the US currency.

There are more than 100 operating companies in the Tata group, of which 32 are listed and the market value of only these firms are taken into account for the group's overall market worth.

The group accounts for 7.60 per cent of the total market capitalisation of Indian markets and commands the highest market value for any business house in the country.

Besides, group firm TCS is currently ranked as the country's most valued company, with a higher market cap than the likes of PSU giant ONGC and Mukesh Ambani-led Reliance Industries.