Microsoft wanted to buy Yahoo for around $40 billion. That didn't work. Microsoft now plans to spend that much buying back stock, while it also increases its shareholder dividend by 18 percent. The company will take on as much as $6 billion in debt to pay for the buyback, which seems to rule out any major acquisition in the near term. Conveniently, the buyback also helps Microsoft founder Bill Gates with one of his biggest problems: selling his $20.3 billion stake in Microsoft in order to fund his nonprofit without killing the company's stock price.Gates sold $350 million worth of shares in August and $2.54 billion worth in 2007, but even at that rate the 52-year old will sell his last Microsoft share right shortly after he's eligible for Social Security, the New York Post reports. Microsoft began a $30 billion stock buyback program in 2004, eventually increasing that round of repurchases to $40 billion.