WASHINGTON—The Securities and Exchange Commission is investigating whether recent stock sales by Tesla Inc. Chief Executive Elon Musk and his brother violated insider-trading rules, according to people familiar with the matter.
The SEC’s investigation began last year after Mr. Musk’s brother sold shares of Tesla valued at $108 million, one day before Mr. Musk polled Twitter users asking whether he should unload 10% of his stake in Tesla and pledging to abide by the vote’s results. Mr. Musk framed the potential sale as a way to cover any taxes he would need to pay if lawmakers imposed new taxes on unrealized capital gains. Mr. Musk began selling billions of dollars worth of stock a few days after his tweet.