Investment firm General Atlantic is expected to buy a 0.1 per cent stake in Facebook, an investment which will value the social networking site at USD 65 billion.

The General Atlantic investment involves the purchase of a block of roughly 2.5 million shares of stock from former Facebook employees, a CNBC report said.

The deal will give the investment firm a 0.1 per cent stake in Facebook.

While the deal between General Atlantic and the selling shareholders has been agreed to, it requires the approval of Facebook and so has not yet been closed, the report said.

The last major investment in Facebook, made in January this year, had valued the company at USD 50 billion.

The California-based company had said it raised USD 1.5 billion in a financing round led by Goldman Sachs and Digital Sky Technologies.

The latest investment in Facebook, which values the company at USD 65 billion, means that the social networking site's value has grown by another 30 per cent in less than two months.

General Atlantic mostly makes investments of USD 50 million to USD 500 million in private and public companies.

Founded in 1980, the firm has USD 17 billion in capital under management.

Companies in the firm's investment portfolio include luxury goods seller Gilt Groupe and software company Kaspersky Lab.