Just when it seemed like things couldn’t get worse in Facebook’s new world of public trading—they did. As Facebook shares tumbled Tuesday, an investor sued the Nasdaq OMZ Group, which hosts the stock, claiming that the exchange operator was negligent in handling orders on Friday during the company’s first day of trading, causing losses for investors. Phillip Goldberg is seeking a class-action suit on behalf of all investors who lost money because Nasdaq delayed or otherwise mishandled their orders Friday. Nasdaq publicly apologized for the technical glitch that caused headaches after Facebook began trading in the morning, its CEO saying the company “clearly had mistakes in the Facebook listing.” Goldberg, a Maryland resident, filed his lawsuit in the U.S. District Court in Manhattan.