Tata group firm TCS today replaced Mukesh Ambani-led Reliance Industries as the country's most valued company in terms of market capitalisation, as investors rallied behind the shares of the IT giant.

At the end of today's trade, Tata Consultancy Services (TCS) commanded a market value of Rs 2,48,116 crore -- higher than Reliance Industries' Rs 2,43,413 crore.

While RIL shares fell 0.25 per cent in an overall lacklustre market, TCS shares rallied smartly by 1.83 per cent on robust buying interest among the investors.

TCS has been steadily closing the gap with RIL in terms of market valuation for the last few trading sessions. The IT firm's lead over RIL in terms of market value is about Rs Rs 4,703 crore or less than two per cent currently.

Way back in 2006, RIL had toppled ONGC to emerge as the country's most valued firm and has largely managed to stay on the top since then, except for a few brief periods in the last ten months.

However, a relatively weaker performance by other blue- chip stocks helped RIL today regain its position as the top-weighted stock on the Indian stock market's key indices, Sensex and Nifty, from the FMCG giant ITC.

At the market closing, RIL commanded a weight of 9.23 per cent, pushing ITC to the second spot with a 9.22 per cent weightage in the Sensex.

ITC had first replaced RIL as the most influential stock on Indian bourses on April 17, but the very next day the energy major regained the top-weighted stock status on the BSE benchmark index Sensex, pushing the FMCG giant down to the second slot.

However, from April 19 till April 30, ITC remained the most influential stock on both Sensex and Nifty, pushing Reliance Industries Ltd (RIL) to second position. While the market weightage is determined by the free-float market capitalisation (value of non-promoter shares), the overall market value includes valuation of promoter shares as well.

RIL has been India's most valued firm for many years, till it lost the pole position briefly in August 2011 to Coal India (CIL). It regained the top slot later but was briefly overtaken by another state-run firm ONGC soon thereafter.

On August 17, 2011, CIL had toppled RIL as the country's most valued company, ending the corporate giant's over four-year rein at the top of the market valuation charts.

Later, India's biggest software services firm TCS pipped RIL to become the largest company by market value on the last day of trading in 2011. However, RIL soon regained its top position, but was overtaken by TCS again today.

A company's market capitalisation is determined by multiplying its share price with total number of shares.

At the end of today's trade, TCS was followed by RIL, ONGC, CIL and ITC among the five most valued companies.