Activist investor ValueAct Capital has taken a $2 billion stake in Microsoft Corp, CNBC reported on Monday, and Microsoft shares leapt to their highest point in seven months.

CNBC's David Faber reported the stake. A representative of ValueAct was not immediately available to comment.

Microsoft shares rose 4.4 percent to $31.06, touching their highest level since last September. With Monday's gains, the stock is up 16 percent this year, putting it on track for its best annual performance since 2009.

One of the chief complaints of Microsoft's investors is that the stock is little changed today from where it was 11 years ago.

At Friday's closing price, a $2 billion stake would represent about 67.2 million shares. That represents less than 1 percent of Microsoft, but would be enough to make ValueAct a top-15 investor in the company, based on Thomson Reuters data.

ValueAct describes its management as being experts in "sourcing investments in companies they believe to be fundamentally undervalued, and then working with management and the company's board to implement strategies that generate superior returns on invested capital."

Most recently ValueAct was involved in pushing industrial machinery maker Gardner Denver Inc to sell itself, an effort that culminated in a $3.74 billion deal with private equity firm KKR.