Investors in Facebook were a bit jittery about the prospect of 804 million more shares of the social networking giant arriving in global stock markets today. But Facebook has surged in price amid a scramble that sent share prices up around 10% at moments. The surge of new shares reflects today's conclusion of the "lockup" period for former employees and those who sold at the public offering. Lockups are typically designed to prevent too many shareholders from selling at a public offering, which could induce volatile price swings. Two more rounds of lockup expirations remain through May.