In just two hours last month, Amazon shares lost $5.7 billion in value right after Donald Trump tweeted the following: “Amazon is doing great damage to tax paying retailers. Towns, cities and states throughout the U.S. are being hurt – many jobs being lost!”

Critics of the President were quick to point out that he was feuding with Amazon’s proprietor, Jeff Bezos, who also owns the anti-Trump Washington Post. His tweet, they said, was the act of an autocrat, of a bully, of a South American caudillo. Worse, it was just the latest in a series of unpresidential tweets. Similar outbursts had damaged the value of Boeing, Lockheed Martin, and Toyota.