The World's Top 10 Billionaires

#1 Warren Buffett

Age: 77

Fortune: self made

Source: Berkshire Hathaway

Net Worth: $62.0 bil

Country Of Citizenship: United States

Residence: Omaha, Nebraska , United States, North America

Industry: Investments

Marital Status: widowed, remarried, 3 children

Education: University of Nebraska Lincoln, Bachelor of Arts / Science
Columbia University, Master of Science

America's most beloved investor is now the world's richest man. Soared past friend and bridge partner Bill Gates as shares of Berkshire Hathaway climbed 25% since the middle of last July. Son of Nebraska politician delivered newspapers as a boy. Filed first tax return at age 13, claiming $35 deduction for bicycle. Studied under value investing guru Benjamin Graham at Columbia. Took over textile firm Berkshire Hathaway 1965. Today holding company invested in insurance (Geico, General Re), jewelry (Borsheim's), utilities (MidAmerican Energy), food (Dairy Queen, See's Candies). Also has noncontrolling stakes in Anheuser-Busch, Coca-Cola, Wells Fargo. Insurance operations flourished in 2007. "That party is over. It's a certainty that insurance-industry profit margins, including ours, will fall significantly in 2008." The Oracle of Omaha issued a challenge to members of The Forbes 400 in October; said he would donate $1 million to charity if the collective group of richest Americans would admit they pay less taxes, as a percentage of income, than their secretaries. Had long promised to give away his fortune posthumously. Irrevocably earmarked the majority of his Berkshire shares to charity in 2006, mostly to the Bill & Melinda Gates Foundation. Gift was valued at $31 billion on day of announcement; donation will far exceed that sum so long as Berkshire shares continue to rise.

#2 Carlos Slim Helu & family

Age: 68

Fortune: self made

Source: telecom

Net Worth: $60.0 bil

Country Of Citizenship: Mexico

Residence: Mexico City , Mexico, Latin America

Industry: Communications

Marital Status: widowed, 6 children

Education: NA

Second-richest man in the world this year; even richer than Microsoft's Bill Gates, at least for now, thanks to strong Mexican equities market and the performance of his wireless telephone company, America Movil. The son of a Lebanese immigrant, Slim made his first fortune in 1990 when he bought fixed line operator Telefonos de Mexico (Telmex) in a privatization. In December, America Movil struck a deal with Yahoo to provide mobile Web services to 16 countries in Latin America and the Caribbean. A widower and father of six, Slim is a baseball fan and art collector. He keeps his art collection in Mexico City's Museo Soumaya, which he named after his late wife. In recent years, he has donated close to $7 billion worth of cash and stock to fund education and health projects, and to the revitalization of Mexico City's downtown historical district.

#3 William Gates III

Age: 52

Fortune: self made

Source: Microsoft

Net Worth: $58.0 bil

Country Of Citizenship: United States

Residence: Medina, Washington , United States, North America

Industry: Software

Marital Status: married, 3 children

Education: Harvard University, Drop Out

Harvard dropout and Microsoft visionary no longer the world's richest man. Blame Yahoo: Microsoft shares have fallen 15% since the company boldly attempted to merge with the search engine giant to better fight Google for Internet dominance. Gates is preparing to give up day-to-day involvement in the company he cofounded 33 years ago to spend more time focused on his philanthropic endeavors. Bill & Melinda Gates Foundation has $38.7 billion in assets, donates to causes aimed at bringing financial tools to the poor, speeding up the development of vaccines (for AIDS, malaria, tuberculosis), bettering America's lagging high schools. Sells 20 million Microsoft shares every quarter, proceeds going to private investment vehicle Cascade; more than half of net worth now outside of Microsoft. Company spent $6 billion to land Web ad firm Aquantive last May. Would-be rival to Apple's iPod, the Zune, not yet a hit. Believes Microsoft's far-flung bets, including 10-year affair with Internet-based television, may soon pay off; says next 10 years will be the "most interesting" in software history.

#4 Lakshmi Mittal

Age: 57

Fortune: inherited and growing

Source: steel

Net Worth: $45.0 bil

Country Of Citizenship: India

Residence: London , United Kingdom, Europe & Russia

Industry: Manufacturing

Marital Status: married, 2 children

Education: St Xavier's College Calcutta, Bachelor of Arts / Science

Heads world's largest steelmaker, $105 billion (sales) ArcelorMittal, which accounts for 10% of all crude steel production. Just delivered 580 tons to be used in construction of the World Trade Center memorial in New York. With 44% stake, is the company's largest shareholder. Longtime resident of London is Europe's richest resident.

#5 Mukesh Ambani

Age: 50

Fortune: inherited and growing

Source: petrochemicals

Net Worth: $43.0 bil

Country Of Citizenship: India

Residence: Mumbai , India, Asia & Australia

Industry: Manufacturing

Marital Status: married, 3 children

Education: University of Bombay, Bachelor of Chemical Engineering
Stanford University, Master of Business Administration

Asia's richest resident heads petrochemicals giant Reliance Industries, India's most valuable company by market cap. His fortune is up $22.9 billion since last year, making him the world's second biggest gainer in terms of dollars. The biggest gainer was his estranged brother Anil, who ranks 6th in the world just behind his older brother. The sons inherited their fortune from their late father, renowned industrialist Dhirubhai Ambani. But they couldn't get along and in 2005 their mother brokered a peace settlement breaking up the family's assets. Mukesh is using some of his money to build a 27-story home.

#6 Anil Ambani

Age: 48

Fortune: inherited

Source: diversified

Net Worth: $42.0 bil

Country Of Citizenship: India

Residence: Mumbai , India, Asia & Australia

Industry: Diversified

Marital Status: married, 2 children

Education: University of Bombay, Bachelor of Arts / Science
University of Pennsylvania Wharton School, Master of Business Administration

The year's biggest gainer, Anil Ambani, is up $23.8 billion in the past year, and is closing gap with estranged brother, Mukesh, who ranks one spot ahead of him in the world at number five. The sons inherited their fortune from their late father, renowned industrialist Dhirubhai Ambani. But they couldn't get along and in 2005 their mother brokered a peace settlement breaking up the family's assets. A marathon runner, his biggest asset is his 65% stake in telecom venture Reliance Communications. He recently raised $3 billion from the highly anticipated initial offering of his Reliance Power, the biggest in India's history. Despite the hype, the stock tumbled 17% immediately after its February listing. In a bid to appease investors, company's board recently approved the issue of bonus shares. Still feuding with brother Mukesh: battling him in court over a gas-supply agreement.

#7 Ingvar Kamprad & family

Age: 81

Fortune: self made

Source: Ikea

Net Worth: $31.0 bil

Country Of Citizenship: Sweden

Residence: Lausanne , Switzerland, Europe & Russia

Industry: Retailing

Marital Status: married, 4 children

Education: NA

Peddled matches, fish, pens, Christmas cards and other items by bicycle as a teenager. Started selling furniture in 1947. Now his company Ikea, which sells hip designs for the cost conscious, is one of the most beloved retailers in the world, with an almost cultlike following. Ikea now has stores in 40 countries, from Sunrise, Florida, to Guangzhou in China. As egalitarian as his brand, Kamprad avoids wearing suits, flies economy class and frequents cheap restaurants. Has been quoted as saying that his luxuries are the occasional nice cravat and Swedish fish roe. Says his home is furnished mostly with his own Ikea products. Last May was awarded the Global Economy Prize by the University of Kiel for his contributions to society.