Elon Musk has made an offer to buy Twitter for $54.20 per share in cash, valuing the company at just over $41.4bn (£31.3bn). In his US Securities and Exchange Commission (SEC) filing, Musk noted that this is a 54 per cent premium over the day before he began investing in Twitter and a 38 per cent premium over the day before his investment was publicly announced. “My offer is my best and final offer and if it is not accepted, I would need to reconsider my position as a shareholder,” he wrote.

Musk became Twitter’s biggest shareholder when he took  a 9.2 per cent stake in the firm last week, but subsequently backed out of an agreement to join the company’s board of directors. In a letter to Twitter Chairman, Bret Taylor, Musk said he had invested in Twitter as he believed in its potential to be the platform for free speech around the globe.

“However,” he wrote, “since making my investment I now realize the company will neither thrive nor serve this societal imperative in its current form. Twitter needs to be transformed as a private company…Twitter has extraordinary potential. I will unlock it.”

Twitter shares jumped from $45.85 on Wednesday to more than $50 in pre-market trading this morning.