Nov. 15 (Bloomberg) -- Billionaire Mukesh Ambani extended his lead over younger brother Anil as the second-richest Indian, after his Reliance Industries Ltd. more than doubled in value as the stock market surged to a record.

Mukesh's net worth soared to $49 billion, ahead of Anil's $45 billion, Forbes magazine said on its Web site. ArcelorMittal Chief Executive Lakshmi Mittal, 57, who has a passport from the South Asian nation and lives in London, held on to the top spot with $51 billion on the list, which showed the four wealthiest Indians have more money than the 40 richest Chinese.

Mukesh and Anil, who split the Reliance Group in 2005 in a deal brokered by their mother, are vying to become India's richest tycoons with forays into oil exploration, media and supermarkets. Mittal's wealth surged a year after creating the world's biggest steelmaker, while Kushal Pal Singh rose to fourth after his DLF Ltd. completed India's biggest initial share sale.

``Both the brothers are very able managers and have focused on the most relevant sectors,'' said Chakri Lokapriya, who manages $950 million of stocks in India, Brazil, Russia and China at BNP Paribas Asset Management U.K. Ltd. in London. ``They recognized the drivers of growth and built businesses to cater to that demand.''

The four richest people in India are worth $180 billion, Forbes said. The fastest economic growth in six decades is spurring consumption and investment in the nation. The worth of India's 40 richest people more than doubled to $351 billion, making them the wealthiest such group in Asia.

Biggest Gainer

Mukesh Ambani, 50, added $30.5 billion to his wealth, making him the year's biggest gainer, Forbes said. The wealth of Anil Ambani, 48, rose $30.2 billion, Forbes said.

Reliance Industries, operator of the world's third-largest oil refinery, accounted for a quarter of the rise in index points of the benchmark Bombay Stock Exchange Sensitive Index this year. The Mukesh Ambani-controlled company's stock has more than doubled, outperforming the Sensex's 44 percent advance.

``There have been several reports in the media about my personal wealth, frankly I'm amused,'' Mukesh Ambani told shareholders last month. ``It matters little to me whether my personal fortunes are measured in billions or millions.''

Mukesh Ambani is building a 27-storey house in Mumbai for his family and this month gave his wife an Airbus 319 as a birthday gift, The Telegraph newspaper reported on Nov. 3.

Reliance Industries spokesman Tushar Pania declined to comment on Mukesh Ambani's net worth.

Childhood Friend

Gains for Reliance Industries have helped companies with links to the Mumbai-based group.

Anand Jain, Mukesh Ambani's friend since childhood, entered the list for the first time with a net worth of $4 billion.

His Jai Corp. has risen more than sevenfold this year as it helps develop special economic zones for Reliance Industries near the commercial capital Mumbai.

The share rally helped Rakesh Wadhawan, whose company Housing Development & Infrastructure Ltd. listed in July, join the list for the first time.

Reliance Industries shares have risen 126 percent this year. Anil Ambani's Reliance Energy Ltd., the best-performing benchmark stock, has increased almost fourfold.

Singh's DLF, India's biggest developer, has almost doubled since its debut on July 5.

Real-estate developers in the country have benefited from a surge in demand and prices as faster growth has attracted more domestic and overseas investors to spend on offices, factories and shops and in turn created more jobs and increased salaries.

Home Demand

India's per capita income has increased 40 percent in the past four years and that in turn has been one factor driving demand for homes.

The price of homes in the southern part of financial hub Mumbai have almost doubled in the past two years, according to data compiled by Bloomberg. Prices in New Delhi, Hyderabad, Bangalore and Chennai too have risen as more local and overseas companies expand operations.

The country's real-estate industry is poised to grow sevenfold to $90 billion by 2015, Moody's Investors Service said in June.

India's economy expanded an average 8.6 percent in the past four years. The government is increasing its spending on infrastructure such as roads, ports, utilities and irrigation networks by 40 percent to 1.34 trillion rupees ($34 billion) this year. This is generating more demand for steel, cement and construction.

Prime Minister Manmohan Singh wants to boost annual economic growth to 10 percent to help eradicate poverty among the nation's 1.1 billion people, half of whom live on less than $2 a day.

The country has among the world's highest prevalence of underweight children at 47 percent, compared with 28 percent in sub-Saharan Africa, according to the United Nations Children's Fund. About 22 percent of the country's 193.6 million households don't have safe drinking water, the 2001 Indian census found.

To contact the reporter on this story: Subramaniam Sharma in New Delhi at ssharma@bloomberg.net.

Last Updated: November 15, 2007 07:08 EST