Don Jeffrey for Bloomberg:

The investors said the members of a proposed class action, or group lawsuit, have lost more than $2.5 billion since the initial public offering last week, in a complaint filed today in Manhattan federal court. They claimed Facebook and the banks didn’t disclose lower revenue estimates.

Morgan Stanley, Goldman Sachs, JPMorgan Chase and others have been named in the lawsuit. The suit claims that Facebook isn’t selling as much advertising shown to mobile users, who make up the company’s greatest growth. The great majority of Facebook’s revenue comes from advertising. A lawyer for the plaintiffs says that underwriters lowered earnings estimates but failed to reveal this except to “a select group of investors.”

In related news, federal regulators are looking into the issue, and Massachusetts officials wasted no time in issuing a subpoena.