Facebook is reportedly looking to expand the size of its already blockbuster IPO by more than 25 percent.
The social-networking giant will file papers with the SEC tomorrow to add 85 million shares to its offering, according to a CNBC report that cited a person familiar with the matter. The additional shares -- as well as the 50.6 million it is making available for over-allotment at the top end of that range -- would bring the size of the IPO up to about 420 million and value the offering at $18 billion.
Facebook had previously expected to sell 337.4 million shares for a deal valued at $14.7 billion.
The report comes on the heels of Facebook expanding the expected pricing range of shares to between $34 and $38 when the company goes public, which is expected to happen Friday. The new price range values the company as high as $104 billion. The previous range of $28 to $35 would have valued the company at $96 billion.
The company, which is expected to price its shares Thursday, claims more than 900 million monthly active users, more than half of whom are active users of the site's mobile service.
Shares are expected to begin trading Friday on the Nasdaq stock exchange under the "FB" symbol.