Top Microsoft Corp. investors are pushing the board of directors to have Bill Gates step down as chairman, people familiar with the matter have told Reuters. Gates cofounded Microsoft in 1975 and is currently helping the company find a replacement for outgoing CEO Steve Ballmer.

　　The report claims three of the top 20 Microsoft Corp. investors, who collectively hold more than 5 percent of the company's stock, are leading the effort, though these parties were not named. Gates owns around 4.5 percent of the company and is its largest individual shareholder.

　　It is not clear if Microsoft's board would listen to the wishes of the three investors. A Microsoft Corp. representative declined to comment when approached by Reuters.

　　"The three investors are concerned that Gates' role as chairman effectively blocks the adoption of new strategies and would limit the power of a new chief executive to make substantial changes," the Reuters report states. "In particular, they point to Gates' role on the special committee searching for Ballmer's successor."

　　The sources also said that they are worried that Gates "wields power out of proportion to his declining shareholding." Gates spends most of his time on his philanthropic endeavors, including the Bill and Melinda Gates Foundation, Reuters said.

　　According to the report, Gates sells about 80 million shares per year as part of a pre-set plan. If continued, he would have no financial stake in Microsoft Corp. by 2018.

　　Ballmer announced in August that he would retire within the next year.Ford CEO Alan Mulally is reportedly a top candidate to replace him.