Twitter's board has recommended unanimously that shareholders approve the proposed $44-billion sale of the company to Tesla CEO, according to a regulatory filing on Tuesday. Musk reiterated his desire to move forward with the acquisition last week during a virtual meeting with Twitter employees, though shares of Twitter remain far below his offering price, signaling considerable doubt that it will happen. Shares rose about 3% to $39 before the opening bell on Tuesday, far short of the $54.2 that Musk has offered for each share. The company's stock last reached that level on April 5 when it offered Musk a seat on the board before he had offered to buy all of Twitter.In a filing with the US SEC on Tuesday detailing a litter to investors, Twitter's board of directors said that it "unanimously recommends to vote for the adoption of the merger agreement." If the deal were to close now, investors in the company would pocket a profit of $15 for each share. Musk said there were unresolved issues, including the debt portion and spam users. "We're still awaiting resolution, and that is a very significant matter," he said, reiterating doubts over Twitter's claims that spam accounts were fewer than 5% of monetizable daily active users.