Mumbai: Tata Group software firm TCS on Thursday dislodged Reliance Industries Ltd (RIL) as the country's most-valued firm for the second time within a week as shares of the billionaire Mukesh Ambani-led corporate giant plunged sharply.

At the end of Thursday's trade, Tata Consultancy Services (TCS) commanded a market value of Rs 2,29,474.38 crore – the highest for any listed company in India and a shade higher than RIL's Rs 2,28,966.07 crore.

TCS had dethroned RIL from the top position for the first time on December 30, 2011 -- the last trading session of that year. However, RIL had regained the pole position on January 2, the first day of trading in 2012.

However, a sharp fall of 2.34 per cent in RIL's share prices again today pushed the company to the second position.

In comparison, TCS shares posted only a modest loss of 0.17 per cent in a lacklustre market. The market barometer Sensex settled 0.16 per cent, or 25.56 points, lower on Thursday.

The market valuation of a listed company corresponds to the cumulative value of all its shares and this figure changes daily as per the change in the stock price.

RIL's market value dipped by about Rs 5,500 crore in today's trade, while that of TCS fell just about Rs 400 crore.

However, TCS currently commands a lead of only about Rs 500 crore, or approximately 0.22 per cent, against RIL in the valuation charts and the market would be keenly awaiting their stock performances in the coming days.

Even the third-ranked company, state-run energy giant ONGC, is not far behind with a market value of Rs 224,410.51 crore, just about Rs 5,000 crore, or close to 2 per cent, below that of the top-ranked TCS.

At the end of today's trade, state-run Coal India Ltd (CIL) was the country's fourth-most valued firm (Rs 202,628.97 crore), followed by IT major Infosys at fifth position (Rs 163,010.51 crore).

RIL has been the country's most-valued firm for a long time, but it has been briefly replaced at the top position by three companies (Coal India, ONGC and TCS) since August, 2011.

Coal India had toppled RIL as the country's most-valued company on August 17, 2011, while the polyester-to-retail conglomerate had slipped to third position after CIL and ONGC two days later on August 19, 2011.

About a week later, RIL regained its top slot on August 23, while CIL slipped to third position. However, ONGC rose to the top slot on August 26, 2011, pushing RIL to second position.

A few days later, RIL again rose to the pole position on August 29, 2011, and had remained there till it lost out to TCS on December 30 that year.