Jeff Bezos step down as Amazon Chief   Jeff Bezos Amazon founder said Tuesday he would stand aside later this year as chief executive of the company he built from a startup into one of the world’s most valuable firms.   The world’s richest person based on his Amazon stake, Bezos said he will transition to the role of executive chair in the third quarter, handing over the CEO role to Andy Jassy, who heads Amazon Web Services. The news came as Amazon reported a blowout holiday quarter with profits more than doubling to $7.2 billion and revenue jumping 44…