Bill Gates is back on top as the richest American, according to Forbes magazine's latest computations, which put the Microsoft mogul's net worth at $57 billion despite increasingly shifting his attention from industry to philanthropy.

His billions were enough to edge investor Warren Buffet for the top spot in this year's Forbes 400, released Wednesday.

The magazine reports that Buffet took the lead from Gates earlier this year, but since then, his shares in Berkshire Hathaway have fallen 15 percent in value.

In the 27th edition of the Forbes 400, the benchmark for making it onto the list of richest Americans was $1.3 billion, about the same as last year. The net worth of all 400 combined is an estimated $1.57 trillion.

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