March 31, 2010, 12:16 AM EDT

By Prashant Gopal

March 31 (Bloomberg) — During the U.S. housing boom, even amateur investors could buy and sell a property within a couple of months and turn a profit. Today there’s nothing amateur about house flipping.

Homes with punctured walls and missing appliances draw multiple offers from professional investors at auctions in foreclosure-ridden states such as Arizona, California, Florida and Nevada. Competition is so stiff that experienced flippers such as Sergio Rodriguez and Brian Bogenn look back with nostalgia at last year, when they turned over 48 residences in the Phoenix area.

“A year ago, bums outnumbered bidders at the courthouse steps,” where many foreclosure auctions take place, Rodriguez said. “Now the bums are way outnumbered.”

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