India’s benchmark stock index rose the most in a month on optimism the biggest weekly tumble in oil since 2011 and slower economic expansion will prompt the central bank to cut rates next week.

Indian Oil Corp. climbed the most in five weeks, leading state refiners higher. Reliance Industries Ltd., owner of the world’s largest refining complex, was set for a two-month high. State Bank of India rallied to a four-year high. Jet Airways (India) Ltd. soared 20 percent amid speculation aviation-fuel costs may fall amid a decline in global crude prices.

The S&P BSE Sensex (SENSEX) rose 1.3 percent to a record 28,813.33 at 12:03 p.m. in Mumbai. The gauge is headed for a sixth weekly gain as falling oil costs helped send consumer inflation below the Reserve Bank of India Governor Raghuram Rajan’s 6 percent goal. The central bank meets on Dec. 2 for its policy review. Gross domestic product probably grew 5.1 percent in the quarter ended September, a Bloomberg survey showed before data due today. That’s slower than the previous quarter’s 5.7 percent.

“Things on the macro-economic front and the political side are absolutely in our favor,” Parag Thakkar, head of institutional sales at HDFC Securities Ltd., told Bloomberg TV India today. He is advising investors to buy shares of Asian Paints Ltd., Castrol India Ltd. and Gulf Oil Lubricants India Ltd. as they are likely to benefit from lower energy prices.

OPEC refrained from cutting output yesterday to ease a supply glut that’s driven oil into a bear market. Brent crude extended its decline after falling to a four-year low earlier this week, while West Texas Intermediate headed for its worst week since 2011. India imports 80 percent of its oil needs.

Rate Outlook

Rajan has held the repurchase rate at 8 percent after raising it three times from September 2013 through January to fight inflation. At the Dec. 2 meeting, 29 of 30 economists in a survey see him holding rates, and one predicts a cut to 7.75 percent. Economists last month advanced forecasts for a reduction to 7.75 percent between April and June, from with an earlier projection of October to December. They now see the benchmark falling to 7.5 percent by the end of 2015.

“The chances of RBI easing monetary policy are brighter now,” Kishor Ostwal, managing director at CNI Research Ltd., said by phone. “The decline in oil is a big positive.”

Indian Oil increased 4.6 percent, taking this year’s gains to 70 percent. Bharat Petroleum Corp. advanced 4.1 percent, the most since Aug. 18. Hindustan Petroleum Corp. jumped 8 percent to an all-time high.

Reliance jumped 2.9 percent after a government panel asked the government to allow the company to recover $ 160 million of cost incurred on the KG-D6 gas field and said the oil ministry should take steps to resolve disputes relating to block.

Aviation Stocks

State Bank surged 4.9 percent to its highest price since November 2010. ICICI Bank Ltd. (ICICIBC) and Axis Bank Ltd. (AXSB) increased 3 percent each to a record.

Jet Airways (India) Ltd. surged the most since April 2009, while SpiceJet Ltd. soared 10 percent to a four-month high.

Asian Paints climbed 5 percent to a record and Castrol India gained for a seventh day. Gulf Oil Lubricants jumped 7.3 to an all-time high.

Global investors bought a net $ 35.7 million of domestic shares on Nov. 26, taking this year’s inflow to $ 15.8 billion, the most among eight Asian markets tracked by Bloomberg.

The Sensex has rallied 36 percent this year, the best performer among the world’s 10 biggest markets. The gauge is valued at 15.9 times projected 12-month earnings, compared with the MSCI Emerging Markets Index’s multiple of 11.3.

To contact the reporter on this story: Rajhkumar K Shaaw in Mumbai at rshaaw@bloomberg.net

To contact the editors responsible for this story: Michael Patterson at mpatterson10@bloomberg.net Ravil Shirodkar, Matthew Oakley