Facebook has filed to raise $5 billion in an initial public offering.

In its regulatory filing Wednesday with the Securities and Exchange Commission, Facebook indicated it hopes to raise $5 billion by selling a small percentage of its shares to the public in its IPO.

The company yesterday named Morgan Stanley as the lead underwriter on the IPO, while reporting a 24-fold increase in sales over the past four years to $3.71 billion in 2011.

A $100 billion market capitalization would value Facebook at 26.9 times trailing 12-month sales. Facebook didn?t specify the number or price of shares it will offer, and the $5 billion amount is a placeholder used to calculate fees and may change.

Co-founded in 2004 by Mark Zuckerberg, Facebook has grown into the world's dominant social- networking site, squelching competitors such as MySpace Inc. with its more than 800 million users. While Facebook?s sales almost doubled last year, the company faces increasing competition from rivals such as Google, which debuted its own social-networking service last year and Twitte, the filing shows.

The stock would trade under the symbol FB on either the Nasdaq Stock Market or the New York Stock Exchange.

Depending on how long regulators take to review Facebook's IPO documents, the company could be making its stock market debut around May.

In a letter included in Wednesday's filing, Zuckerberg paints a rosy, idealistic picture of Facebook.

"Facebook aspires to build the services that give people the power to share and help them once again transform many of our core institutions and industries," he wrote.

Zuckerberg also pledged to stay true to Facebook's scrappy roots even on the road to becoming a multinational corporation.

"The word 'hacker' has an unfairly negative connotation from being portrayed in the media as people who break into computers," he wrote. "In reality, hacking just means building something quickly or testing the boundaries of what can be done."

According to the filing, Zuckerberg is the company's top holder with 28.4 percent of the shares, the filing shows. He also has proxy agreements with fellow stockholders that potentially give him voting control over more than half the shares. Accel Partners remains the top outside stakeholder with 11.4 percent of the investor votes, while Dustin Moskovitz, one of Zuckerberg?s co-founders, holds 7.6 percent voting power.

In outlining its potential risks in the filing, Facebook cited hacker attacks, regulatory scrutiny, a shift to mobile technology and rivals such as Google+. The company also said it would face competition in China if it manages to gain access to that market, where its site is currently blocked.

Facebook is also increasing its focus on mobile technology to take advantage of the shift to smartphones and tablets. It expects its next 1 billion users to come mainly from mobile devices, rather than desktop computers.

As the site's popularity grew, banks, hedge funds and mutual fund companies started buying stock. In January 2011, Facebook said it raised $1.5 billion in a financing round led by Goldman Sachs that valued the company at $50 billion. Goldman Sachs, funds managed by the firm, and Digital Sky Technologies bought $500 million of stock, while Goldman Sachs offered $1 billion of shares to non-U.S. clients.