Mumbai: Infosys regained its status as the most influential stock from Reliance Industries (RIL) on the stock market barometer, Sensex, as the shares of the IT giant outperformed that of Mukesh Ambani-led corporate giant. Infosys shares on Monday gained 1.9 percent in a volatile market but that of RIL plunged 2.5 percent. At the end of the day, Infosys carried 9.59 percent weight on Sensex - a shade above RIL's 9.58 percent and highest among the 30 constituents of the BSE index. On January 12, Infosys had slipped to the second position behind RIL in terms of the weight on Sensex - which determines the impact of a stock on the daily movement of the BSE index - after a sharp plunge of 8 percent in its share price. Infosys had first replaced RIL at the pole position in December, after the two stocks have outscored each other on several occasions as per the movement in their stocks. The Sensex weight of a stock is determined on the basis of a company's free-float market capitalisation or the value of shares owned by non-promoter stakeholders that are freely available for trade. At the end of yesterday's trade, Infosys' free-float market cap stood at 128,566.80 crore, as against RIL's 128,479.68 crore. The position of the two stocks might change again on the Sensex weight list, as the difference between the two is very narrow. In terms of full market cap, which includes value of promoter shares as well, RIL is the country's most valued firm (233,599.42 crore). With a full market cap of 151,255.06 crore, Infosys is ranked sixth after RIL, ONGC, TCS, Coal India and ITC. From its fifth position previously, Infosys had slipped to sixth on January 12 after its share price plunged sharply on account of its weak full-year revenue outlook.