Twitter has appointed Elon Musk to its board after the billionaire co-founder and chief executive of electric vehicle maker Tesla, bought a 9.2 percent passive stake in the social media company to become its single largest shareholder. Musk will “serve as a Class II director with a term expiring at the company’s 2024 annual meeting of stockholders,” the company said in a Securities and Exchange Commission filing ahead of markets opening on Tuesday in the US. “For so long as Musk is serving on the Board and for 90 days thereafter, Musk will not, either alone or as a member of a group, become the beneficial owner of more than 14.9 percent of the company’s common stock outstanding at such time, including for these purposes economic exposure through derivative securities, swaps, or hedging transactions,” the statement said. Twitter chief executive Parag Agrawal said he is “excited” about Musk’s appointment. “Through conversations with Elon in recent weeks, it became clear to us that he would bring great value to our board,” he said in a tweet. “He’s both a passionate believer and intense critic of the service which is exactly what we need on Twitter, and in the boardroom, to make us stronger in the long-term. Welcome Elon!” Shares of Twitter jumped about 7 percent in pre-market trading to $53.38 on Tuesday. Twitter’s stock price had soared more than 27 percent on Monday after Musk bought more than 73.4 million shares of the company, worth about $3 billion, according to an SEC filing. “Overnight, Elon Musk stole the headlines, announcing with a swipe of his debit card, the purchase of a 9.2 per cent stake in Twitter,” said Jeffrey Halley, a senior market analyst at Oanda. “That was enough to light the fires in the tech space with the Nasdaq booking decent gains, with the Musk feel-good spreading to the US equity space in general.” The Nasdaq jumped 1.90 percent on Monday, while the S&P 500 gained 0.80 percent and the Dow Jones Industrial Average added 0.30 percent. Twitter has a market value of about $40bn as of the close of trading on Monday. Its shares have been up about 17 percent since the start of this year.