Private equity firm Hellman & Friedman is looking to cash out DoubleClick Inc., according to Reuters.

It is rumored that Microsoft is among the suitors.

DoubleClick might indeed go public again, but a purchase by Microsoft could help the company with its AdCenter, which has lagged behind Google and Yahoo!.

It could be a sound investment for Microsoft. Hellman & Friedman listed the price tag at around $2 billion, according to ZDNet, but the company was acquired in 2005 for 1.1 billion.