Proxy adviser Institutional Shareholder Services on Wednesday recommended investors withhold their support from five Facebook Inc. directors, including Chief Executive Mark Zuckerberg and Chief Operating Officer Sheryl Sandberg, citing issues including the social media company's lack of a formal nominating committee.

ISS also suggested investors vote "for" shareholder proposals calling for the company to study establishing a board committee on risk management, and to report on content management controversies, according to copy of its recommendations seen by Reuters.