(Bloomberg) — Elon Musk’s fortune is coming back down to Earth.After an epic six-day rally, Tesla Inc. shares tumbled 17% Wednesday, the most in eight years, cutting the chief executive officer’s fortune by $5.9 billion. The stock had surged to a record close of $887.06 a day earlier, rocketing Musk to No. 20 on the Bloomberg Billionaires Index, just past John and Jacqueline Badger Mars, the owners of candy-maker Mars Inc.Musk, 48, ended the day at No. 25 on the ranking with a net worth of $39.3 billion. He started the year at No. 35.Even before the plunge, investors and […]