Explainer: What would it take for U.S. regulators to break up Facebook?

Facebook Inc co-founder and Mark Zuckerberg's former college roommate Chris Hughes urged U.S. regulators to break up the social media company in a New York Times opinion piece on Thursday.It is rare to break up a company but not unheard of, with Standard Oil and AT&T being the two biggest examples.Hughes' call to split Facebook from WhatsApp and Instagram followed a March pledge by U.S. Senator Elizabeth Warren, who is running for the Democratic presidential nomination for the 2020 election,