Facebook CEO Mark Zuckerberg Rings Nasdaq Opening Bell

Mark Zuckerberg, chief executive officer of Facebook Inc., center, Sheryl Sandberg, chief operating officer of Facebook, center left, and Robert Greifeld, chief executive officer of Nasdaq OMX Group Inc., center right, applaud after remotely ring the opening bell for trading at the Nasdaq MarketSite from the Facebook campus in Menlo Park, California, U.S., on Friday, May 18, 2012. Facebook Inc. is set to start trading today after a record initial public offering that made the social network more costly than almost every company in the Standard & Poor's 500 Index. Photographer: Zef Nikolla/Facebook via Bloomberg