Behind Elon Musk’s Twitter poll is a tax bill coming due

Elon Musk may have already been compelled to sell a sizable portion of his Tesla shares even if he had not issued an unusual Twitter pledge over the weekend. Musk on Saturday polled Twitter users on whether he should sell 10% of his stake in his company. The poll appeared to be a response to a Democratic proposal to tax the unrealized gains of billionaires.