At the end of trade today, RIL commanded 9.33% weight in the 30-share Sensex, while ITC had 9.27% weight, followed by Infosys with 8.05%.
Shares of RIL ended the day 3.4% higher at Rs 889.65, while ITC was up 0.53% at Rs 285.15.
The RIL counter saw good buying amid government virtually deregulated diesel prices allowing "small" hikes over a period of time.
Experts said the counter also saw activity ahead of its earnings tomorrow.
"The bullishness in the stock price also stemmed from the expectation of healthy improvement in refining margins in its quarterly results," said Milan Bavishi, Head Research, Inventure Growth & Securities.
Weight of a stock is measured by the value of a company's free-float or non-promoter shares that can be freely traded in the market.
ITC had first replaced RIL as the most influential stock on Indian bourses on April 17 last year, but the very next day the energy major regained the status.
RIL also remains the country's most valued company in terms of market capitalisation. The energy major commands a market value of Rs 2,87,848 crore.
ONGC is the second most valued company with a m-cap of Rs 2,69,070 crore, followed by TCS (Rs 2,66,622 crore), ITC (Rs 2,24,649 crore), and Coal India (Rs 2,22,588 crore).