At close of trade on Monday, RIL's m-cap stood at Rs 8,19,073.62 crore, which is Rs 7,226.43 crore more than that of TCS.
Reliance Industries Ltd (RIL) was the only firm among the top 10 companies to post a gain in its market valuation.
Revision in the outlook follows RIL announcing plans to sell a 20 pc stake in its oil-to-chemical division to Saudi Aramco.
RIL also entered a deal with BP to sell 49 pc stake in its fuel marketing business in India for USD 1 billion.
The oil-to-telecom giant saw its scrip jump 9.72 per cent to close at Rs 1,275 on the BSE.
The scrip opened the day on a bullish note and jumped 12.09 per cent to Rs 1,302.50 on the BSE.
Reliance's Mukesh Ambani unveiled promised to make connectivity infrastructure free for nascent stage firms.
The company is preparing its Jamnagar complex to be future ready as fuel demand undergoes change.
TCS, HDFC, Infosys, Kotak Mahindra Bank and ICICI Bank were the other firms which saw a rise in their market capitalisation.
Complexity index designates capabilities of a refinery to upgrade lowest quality crude to highest quality refinery products.