The juggernaut social media website Facebook was once the property of four Harvard classmates. On Friday, it will now be shared not four ways but more than 421 million ways.

The website, which has accrued more than 900 million users since its launch from a Harvard dorm room in 2004, plans to go public on Friday. Two days ahead of the slated initial public offering, the company announced that it would expand the number of shares it will offer by 25 percent, bringing the total traded shares to 421 million.

The IPO will be one of the largest in financial history, and Facebook stands to raise more than $18 billion as investors buy the company’s shares on the traded markets.

Brokerage companies, which handle stock trades for investors, have been overrun by high demand for Facebook shares. In fact, Morgan Stanley, TD Ameritrade, Fidelity, and other brokerage companies stopped accepting orders on Thursday.

Seeing the high investor demand for Facebook shares, the company raised the price of its stocks from $34 to $38 on Thursday morning. At the new price, the company could be valued as high as $104 billion.

—Staff writer Fatima N. Mirza can be reached at fmirza@college.harvard.edu.