InvestmentsTop Global NewsMarketsReal Estate Musk’s 2018 anti-union tweet violated labor law, says US labor board By financialnews_rlv83x - March 26, 2021 0 175 Tesla Inc Chief Executive Officer Elon Musk’s 2018 tweet threatening employees would lose their stock options if they formed a union was illegal and should be deleted, the U.S. National Labor Relations Board said on Thursday.