Morgan Stanley defended its role in Facebook's initial public offering after a Massachusetts regulator subpoenaed the bank over talks between an analyst and investors about the social media company's revenue outlook.
"Morgan Stanley followed the same procedures for the Facebook offering that it follows for all IPOs," said Pen Pendleton, a spokesman for the New York-based investment bank.
"These procedures are in compliance with all applicable regulations."
Facebook shares have plunged in the three days since the second-largest IPO in US history, prompting investors to blame Morgan Stanley, the lead underwriter.
The bank said it sent a copy of a revised prospectus that Facebook filed on May 9 to all of its institutional and retail investors.