Facebook expands IPO size, aims for $15 billion: source SAN FRANCISCO (Reuters) - Facebook Inc is increasing the size of its IPO by 85 million shares to about 422 million, a source familiar with the matter told Reuters, raising more than $15 billion in Silicon Valley's largest market debut. The increased volume comes just after the world's No. 1 social network hiked its price range to $34 to $38 a share, from $28 to $35 previously. Facebook had originally intended to sell about 337.4 million shares. At a mid-point of $36, the company would raise $15.2 billion in one of the largest U.S. initial public offerings ever. Reporting by Olivia Oran; Editing by Paul Tait