CNBC is reporting that Microsoft could want a piece of Dell even after its privatization. Sources speaking to CNBC's David Faber tell him that Redmond might invest $1 billion to $3 billion in the company.

Microsoft is claimed to be in talks with private equity firm Silver Lake and Michael Dell, both of whom are believed to be working on a leveraged buyout of the PC builder. Microsoft has had dealings with Silver Lake before; in 2011 it took Skype off the investment company's hands. With the buyout valuation estimated at around $22 billion, Microsoft would only be a bit part player in any buyout, but it would be able to use its position to influence the direction of the company. Faber's terminology was unclear, but it's being interpreted to mean that Microsoft would provide a loan that would at some point convert to preferred stock.

This could prove complicated for Dell. Dell currently has a substantial Windows PC business; it's still the third biggest PC vendor in the world. But this is a business that is suffering on the back of extended upgrade cycles and thriving tablet sales. The reported motivation for going private is to give the company room to "reinvent" itself. This reinvention might see it try to break away from its dependence on Windows PC sales, just as IBM did in 2005 when it sold its consumer PC division to Lenovo, and as Leo Apotheker intended to do during his brief and tumultuous tenure as CEO of HP.

Such a move may be good for Dell, but it's less clear that it would be good for Microsoft. Microsoft's investment could give it the opportunity to push back against such plans.

Investing in Dell might also cause some disquiet among Microsoft's other PC partners. Acer, in particular, has already voiced its dissatisfaction that the software giant has decided to enter the tablet market with Surface. Having a vested interest in one PC OEM in particular might be viewed in a dim light.

However, this is not the first time that Microsoft has invested in a company that builds computers—in 1997 it invested $150 million in Apple.