Steve Ballmer is to sell a significant proportion of his Microsoft stock, giving himself around a $2bn bonus this year.
In a statement Ballmer said he was just as confident in Microsoft's future as ever but was making the sale for "financial diversification and to assist in tax planning before the end of the calendar year."
"Even though this is a personal financial matter, I want to be clear about this to avoid any confusion," Ballmer said.
"I am excited about our new products and the potential for our technology to change people's lives, and I remain fully committed to Microsoft and its success."
Ballmer made the announcement days after the state of Washington voted down proposition 1098, created by Bill Gates' father, that would have increased taxes on income and dividends to pay for better schools and healthcare.
Ballmer campaigned against the law, contributing over $400,000 in funds to defeat the proposition. The move pitted him against Bill Gates, who campaigned for the tax rise to the annoyance of senior Microsoft staff.
According to some reports Ballmer has already completed a large chunk of the sales.
The US is currently debating allowing tax breaks that disproportionally benefit the wealthiest citizens introduced by former President Bush to lapse, leaving high rate payers facing increased tax bills next year.
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