Facebook has reportedly raised funds from Goldman Sachs and a Russian investor in a deal valuing the social networking site at $50bn (£32.3bn).
The New York Times said that Goldman was investing $450m in Facebook, and Digital Sky Technologies another $50m.
The paper, citing unnamed sources, said the terms of the deal implied a value for Facebook of just over $50bn.
Goldman's involvement could also raise speculation that Facebook might float on the stock market.
A Facebook spokeswoman told the BBC that the company was not commenting on the New York Times story. Goldman also declined to comment.
If valued at $50bn, Facebook is worth more than eBay and Time Warner.
The fresh investment is expected to be used to fund develop of new products and possibly make acquisitions, the New York Times said.
It may also enable Facebook employees and early investors to cash in some of their stakes.
The paper said the Securities and Exchange Commission was looking at the growth in the private market for trading in companies like Facebook, Twitter, and LinkedIn.
Regulators are concerned that, with this private market booming, companies are able to circumvent public disclosure requirements.
Further scrutiny by the SEC could help push Facebook towards a public listing, although the company's founder, Mark Zuckerberg, has denied there are plans for a flotation.