Bill Gates remains the richest person in the United States with a fortune of $66 billion in 2012, up 10 percent from last year, Forbes magazine said Wednesday. Behind the Microsoft co-founder and philanthropist come investment guru Warren Buffett with $46 billion, then Oracle co-founder Larry Ellison with $41 billion. White Gates fattened his net worth by seven billion dollars, Ellison sweetened his wealth by eight billion dollars, an increase of more than 20 percent from 2011. Not so lucky was Facebook founder Mark Zuckerberg. He lost $8.1 billion and has dropped to 36th place on the Forbes ranking with a net worth of $9.4 billion. Actually, Zuckerberg is tied with two other people in that spot: pipeline magnate Richard Kindler and media mogul Rupert Murdoch. Financier George Soros dropped from the top ten of the Forbes ranking to 15th place, with $19 billion. New York City Mayor Michael Bloomberg returned to the top ten as he increased his fortune by $5.5 billion to $25 billion. Forbes said the combined net worth of the 400 richest Americans was $1.7 trillion, up 200 billion from 2011, thanks to a recovery in share prices, a rise in real estate prices, especially in Los Angeles and New York, and a jump in the value of artworks, Forbes said.