Most outsiders expect that Microsoft will appoint a new CEO in the remaining weeks of 2013, or if not then, early in 2014.
Gates also praised Ballmer's 13-year reign as Microsoft's CEO and his friend's and former college dorm mate's 33 years with the company.
"We clearly share two other things, as well," Gates said near the end of his speech, at one point briefly choking up. "We've got a commitment to make sure that the next CEO is the right person, for the right time, for the company we both love. And we share a commitment that Microsoft will succeed as a company that makes the world a better place."
On Tuesday, Microsoft's stock closed down 1.2% for the day. Even with that decline, its share price was up 13.4% since Aug. 22, the day before Ballmer announced his retirement plans.
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