The 28-year-old Facebook CEO and billionaire — after mostly staying out of the political fray while running his company’s day-to-day operations — is joining with other executives to form an issues advocacy organization, with an initial focus on comprehensive immigration reform, according to sources familiar with the discussions…

News of the group was first reported by the San Francisco Chronicle, which said Zuckerberg has committed millions to the effort. A source told POLITICO that the group is likely going to be a nonprofit.

Other than Zuckerberg, a central person involved in the discussions is Joe Green, co-founder of NationBuilder and Causes, who was Zuckerberg’s roommate at Harvard University. Green recently resigned as president of NationBuilder and is now an entrepreneur in residence at Andreessen Horowitz, the venture firm.