The speculation is over. Facebook Wednesday filed for an initial public offering to raise up to $5 billion in a deal that could ultimately value the social network at an estimated $75 billion to $100 billion. Though less than the $10 billion rumored, the transaction would be the largest IPO ever by an Internet company, easily eclipsing the $1.9 billion raised by Google in 2004.

The $5 billion is seen as just a preliminary fund-raising target that Facebook could expand to the expected $10 billion to meet investor demand. The company’s actual market debut isn’t expected until this spring, when it will set pricing for its shares.

In a letter to potential shareholders, Facebook CEO Mark Zuckerberg reaffirmed the compay’s often-stated goal of making the world more open and connected. “We think a more open and connected world will help create a stronger economy with more authentic businesses that build better products and services,” he wrote. If nothing else, the IPO will certainly provide more money for Facebook to create better services.