Bangalore: Setting the stage for the much-awaited trading of Facebook, its founder Mark Zuckerberg today rang the opening bell at the Nasdaq stock exchange.Zuckerberg rang the bell from the headquarters of Facebook in California. The popular social networking site would be the largest US company at its debut with a market value of $104 billion. Standing outside his Menlo Park company headquarters, Zuckerberg was surrounded by executives and hundreds of employees as he rang the opening bell and signed on a glass podium. Facebook COO Sheryl Sandberg was standing beside Zuckerberg, who hugged his fellow executives after ringing the opening bell. Wearing his trademark grey hoodie, Zuckerberg also waved at this employees. Shares of Facebook shares would start trading on the Nasdaq under the ticker symbol 'FB' in a short while from now. The stock has been priced at USD 38 and the IPO is expected to mop up anywhere between USD 16-18 billion.Facebook put up 421 million shares of its common stock up for sale. Morgan Stanley, JP Morgan, Goldman Sachs, Bank of America Merrill Lynch and Citigroup, are among the players managing the offer.At USD 16 billion, the size of Facebook's IPO would be the third-largest for a US company. The largest offering ws that of Visa, that raised$17.9 billion in 2008.