Rebekah Mercer is a billionaire American conservative activist, heiress, Republican donor, and philanthropist. As the eldest daughter of hedge fund billionaire Robert Mercer, she serves as the chair and operational leader of the Mercer Family Foundation, where she is a principal director. The foundation has channeled hundreds of millions of dollars to conservative, libertarian, and Republican organizations, think tanks, and advocacy groups. She is known for her significant role in funding right-wing media and political campaigns, having played a key part in the 2016 Trump presidential campaign and transition team. Mercer was a primary investor in Cambridge Analytica, a controversial data analytics firm that faced widespread scrutiny for its alleged misuse of Facebook user data for political microtargeting and election influence. She held a board position at Breitbart News, a prominent right-wing news and opinion website, and co-founded the Reclaim New York Initiative, a government watchdog group. Her philanthropic and political activities reflect a strong commitment to conservative and libertarian ideologies, often supporting causes aligned with climate change denial, anti-immigrant policies, and the promotion of alternative media narratives, underscoring a deep commitment to shaping the American political landscape through strategic funding and direct engagement.