The Facebook IPO

Facebook to Increase IPO Deal Size by 25%: Source

Kate Kelly|Reporter

Facebook plans to increase the size of its IPO by 85 million shares, says someone familiar with the matter, a move that could value its upcoming offering at as much as $18.5 billion.

Scott Eells | Bloomberg | Getty Images

The social network’s 25% upsize plan will be filed with regulators at the U.S. Securities and Exchange Commission Wednesday morning, this person said.

Facebook’s expected move takes the size of its new issue from roughly 340 million shares to roughly 420 million, a change that, combined with the greenshoe – additional shares that could be sold by bankers in the aftermath of the IPO – could value the total deal at nearly $20 billion.

A final decision on Facebook’s IPO price, which is expected to be somewhere between $34 and $38 per share, will be made Thursday evening.

- By CNBC's Kate Kelly