Houston: Seeking to raise USD 5 billion, giant social networking site Facebook has filed for its long awaited initial public offering.

The IPO of the social network site, having over 800 million active users, is expected to be the biggest sale of shares by an internet company so far.

It filed paperwork to go public on Wednesday.

Facebook's IPO would surpass rival Google's 2004 offering of USD 1.9 billion. Earlier Google held the record for the largest US Internet IPO.

For longtime followers of the social network, this is an exciting time and a culmination of the site's eight-year rise from Mark Zuckerberg's Harvard dorm room to world domination.

Investment bank Morgan Stanley will act as lead underwriter, with Goldman Sachs and JP Morgan and others to take secondary positions.

Shares are expected to hit the market in May under the stock symbol "FB".

The company is seeking to raise USD 5 billion, according to this early filing, amounting to a lofty (and still tentative) valuation of almost USD 100 billion.

Going public also provides a rare glimpse into the internal stats previously kept private.

The service has 845 million active users, nearly half of which log in and actuate 2.7 billion likes and comments each day.

It also shed light on the company's prior revenue and earnings, with profits of USD 229 million and USD 606 million in 2009 and 2010, respectively easily bested by a whopping USD 1 billion in 2011.

As for the Zuckerberg, his 2011 salary of USD 500,000 will be cut to USD 1 as of January 2013, but he'll be more than comfortable, thanks to a 28.4 per cent stake in the company.

Meanwhile, Wall Street banks hope the IPO opens door to more work with the company down the line, and that work can mean more fees.

The Morgan Stanley brokers hope an IPO leads to handling money for some of those suddenly rich Facebook employees.