FACTBOX: Facebook's IPO: who gets rich?

By Poornima Gupta and Gerry Shih

SAN FRANCISCO (Reuters) - The rich are going to get richer when Silicon Valley's biggest IPO starts trading on Friday.

Facebook this week raised the number of shares it intends to float by 25 percent to 421 million shares, and lifted the target price range to $34-$38 per share as investors clamored for a slice of the third-largest IPO in U.S. history.

As a result, the No. 1 social network and its shareholders will now collectively reap more than $15 billion from the initial public offering - a $5 billion hike from early May, when Facebook sought an IPO of roughly $11 billion.

The company itself will not float extra stock, Facebook said in a Wednesday filing with the U.S. Securities and Exchange Commission. But early investors like venture capital firm Accel Partners; Tiger Global Management, the hedge fund; Goldman Sachs ; PayPal co-founder Peter Thiel; and companies tied to Russian tycoon Yuri Milner are cashing out with additional sales to the tune of as much as $3.8 billion.

The largest seller remains Accel Partners, which will make almost $1.77 billion if the shares sell at $36, the mid-point of its indicative price range.

Milner's Digital Sky Technologies Global Ltd will unload an additional 19 million shares, bringing the value of its sale to more than $1.6 billion. Mail.ru , another firm controlled by the Russian mogul, will sell a stake worth $705 million.

And Goldman is more than doubling the number of shares it is selling, from 13.2 million to 28.7 million. The new sale amount will bring the bank more than $1 billion.

Those holding onto their stakes for now include: Napster co-founder and Facebook founding president Sean Parker; co-founder and Zuckerberg's Harvard roommate Dustin Moskovitz; various Facebook executives; and venture capital firm Andreessen Horowitz.

Zuckerberg, who started Facebook in 2004 from his Harvard dorm room, is selling shares worth a little over $1 billion.

Mark Pincus, co-founder of the gaming company Zynga Inc , is set to get his second payout in six months. He still stands to make almost $32 million, on top of his take when the social gaming giant he co-founded went public last year.

Assuming a mid-point price of $36, following are details on the amount the selling stockholders will make:

Accel Partners total $1.77 billion

Digital Sky $1.6 billion

Technologies

Mark Zuckerberg $1.08 billion

Goldman Sachs $1.03 billion

Tiger Global Management $842.7 million

MAIL.RU $706 million

Peter Thiel $606 million

Meritech Capital $252 million

Greylock Partners $274 million

Microsoft Corp $236 million

Elevation Partners $166.4 million

Mark Pincus $36.3 million

Reid Hoffman and family $34 million

(Reporting By Poornima Gupta and Gerry Shih; Editing by Richard Chang)