Elon Musk Offers to Buy Rest of Twitter for $54.20 a Share

Elon Musk has offered to buy Twitter Inc. for $54.20 a share in cash, calling the bid his “best and final offer” for the social-media platform.

“If it is not accepted, I would need to reconsider my position as a shareholder,” said Mr. Musk, who earlier this year built a 9.2% position in the stock, making him the company’s largest shareholder.

Mr. Musk said the offer represented a 54% premium over the day before he began investing in Twitter and a 38% premium over the day before his investment was publicly announced.

On Wednesday, shares closed at $45.85. Twitter shares were up 11% premarket to $50.80 on Thursday morning.

The nonbinding proposal would take Twitter private in a deal valuing the company at more than $43 billion.