Shares of Reliance Industries today crossed its buyback threshold limit of Rs 870 apiece for the first time since the repurchase offer began in February. The RIL scrip surged nearly four per cent helping the company regain its position as the country's most valued firm from software giant Tata Consultancy Services (TCS). As the share price of Reliance Industries Ltd (RIL) gained 3.89 per cent to close at Rs 873.65,the company's market value also soared to Rs 2,82,672 crore - above TCS' Rs 2,62,443 crore,which slipped to second place. According to the information available with the bourses,Mukesh Ambani-led RIL that began a buyback programme of Rs 10,440 crore early this year,has so far purchased shares worth Rs 3,198.35 crore through open market route. This translates to about 30.63 per cent of the total Rs 10,440 crore amount earmarked for purchase of shares via buyback. Between February 14 and September 11,the country's most valued firm purchased 3.90 crore shares at an average price of Rs 819.25 apiece. Although,the buyback begun in February,but it gained momentum from May when it had touched Rs 692 level. Ever since the buyback offer launched early this year,the company has never crossed the threshold limit of Rs 870. Market experts said the oil and gas giant is buying back shares aggressively from the open market with an aim to shore up stock valuations.