New Delhi: Microsoft-co founder, Paul Allen, has won the title of the world's wealthiest bachelor, with an estimated personal fortune of $15.3 billion, according to a ranking by Wealth-X - a global wealth intelligence provider.Allen, who has never married, is a business tycoon, investor and philanthropist, owns two sports teams –the Seattle Seahawks, an American football team and the Portland Trail Blazers, a basketball team.Recently in November, Allen purchased an eight-bedroom mansion in the Silicon Valley town of Atherton for $27 million, which sprawls over 22,000 square feet, or a 5 car garage.According to Trulia, Allen also has “a state-of-the-art residence on tony Mercer Island, with a yacht parked out front. He also owns multi-million-dollar properties all over the world, including estates in France, Hawaii, Malibu, Manhattan, Idaho, Beverly Hills and London.The survey by Wealth-X found that world's 10 single billionaires have an average age of 54.5.Here is a list of the 10 richest bachelors in the world:10. Charles Butt, 75 -- $2.9 billionCharles Butt, 75, is chairman and CEO of H.E. Butt Grocery in Texas. 9. Alejandro Santo Domingo Davila, 36 -- $3.9 billionAlejandro Santo Domingo Davila, 36, is the second-richest person from Colombia. He inherited the wealth from his father, Julio Mario Santo Domingo Pumarejo, who died in 2011. The Santo Domingo Group has interests in a range of businesses including SABMiller.8. Andreas von Bechtolsheim, 58 -- $4.4 billionAndreas "Andy" von Bechtolsheim, 58, co-founded Sun Microsystems. He is chairman of networking company Arista Networks. The German bachelor is worth an estimated $4.4 billion.7. Scott Duncan, 53 --$5.3 billionScott Duncan, 53, is a billionaire heir to the Duncan family fortune. Scott Duncan is one of four children of the late energy pipeline entrepreneur Dan Duncan, the former richest man in Houston, who died in 2010 at age 77. Scott added $1 billion to his fortune in the last year as the company's share price climbed by one-fourth.6. Marcos Mera, 42 -- $5.7 billionMarcos Mera, 42, inherited the wealth of his late mother, Rosalia Mera, when she died in August. She was the world's wealthiest self-made woman from co-founding Spanish clothing brand Zara.5. David Geffen, 70 -- $6.6 billionDavid Geffen, 70, is an American businessman who co-founded DreamWorks Animation SKG. 4. Xavier Niel, 46 -- $8 billionForbes touts Xavier Niel, 46, as France's Internet king. His company, Iliad, is the parent of Free, a telecom. Last year, Niel launched mobile broadband company Free Mobile. He is co-owner of the French newspaper Le Monde.3. Mikhail Prokhorov, 48 -- $9.3 billionMikhail Prokhorov, 48, is owner of NBA team the Brooklyn Nets. The Russian entrepreneur and politician is the 69th richest person on the planet, according to Forbes. 2. Giorgio Armani, 79 -- $10.9 billionItalian fashion designer Giorgio Armani, called "the fashion world's perennial bachelor" by Wealth-X, has a net worth of nearly $11 billion.1. Paul Allen, 60 -- $15.3 billionAllen's eight-bedroom mansion in the Silicon Valley town of Atherton has the most expensive zip code in the U.S., according to Forbes.