Former Microsoft CEO and major Twitter shareholder Steve Ballmer told CNBC on Thursday he's been on the phone with Twitter CEO Jack Dorsey, and he thinks it's time to focus full-time on the ailing social media brand.
"Every time I talk to Jack, the message is, 'We need more. More innovation. Move, move, move,'" Ballmer said on "Squawk Box." "Get the cost base right and move forward."
Shares of Twitter tumbled about 10 percent on Thursday morning after the company announced quarterly revenue that was far short of expectations and worse-than-expected forward guidance. Dorsey is also the CEO of Square.
"Running two companies is not the best idea," Ballmer said. "And I'll stand by the notion that Jack's a very creative, innovative guy, as well evidenced by the fact that he started two amazing companies. ... I give him credit for that, and I think now's the time to focus down, at least from my perspective, on the stock I own."