NEW YORK (Reuters) – The net worth of the richest Americans grew by 13 percent in the past year to $1.7 trillion, Forbes magazine said on Wednesday, and a familiar cast populated the top of the annual list, including Bill Gates, Warren Buffett, Larry Ellison and the Koch brothers. The average net worth of the 400 wealthiest Americans rose to a record $4.2 billion, up more than 10 percent from a year ago, while the lowest net worth came in at $1.1 billion versus $1.05 billion last year, the magazine said. Seven in ten of the list's members made their fortunes from scratch. …
