Tesla CEO Elon Musk struck a deal just before 3 p.m. EST to acquire social media giant Twitter.

Twitter's board and Tesla CEO Elon Musk had negotiated into the early hours of Monday over his bid to buy the social media platform. The negotiations followed a special meeting of the Twitter board on Sunday, the Times said, basing its report on two people with inside information.

Twitter is poised to accept Musk's offer for around $43 billion in cash, the price the chief executive of Tesla, Inc. has called his "best and final" offer for the social media company, people familiar with the matter tell Reuters.

Twitter may announce the $54.20-per-share deal later on Monday, once its board has met to recommend the transaction to Twitter shareholders, according to the Reuters sources. It is always possible that the deal collapses at the last minute, the sources added.

Twitter (TWTR) was up 2.2% in premarket trading, to $51.50. It stock was halted at 2:41 p.m. at $51.63.