Ira Leon Rennert, born on May 31, 1934, is an American billionaire industrialist, investor, and businessman, widely recognized as the chairman and CEO of the Renco Group, a private holding company with diverse interests spanning metals, mining, and manufacturing sectors. He is known for his substantial philanthropic contributions, particularly to pro-Israel causes and organizations, and has been identified as a major donor to figures like Howard Kohr. Rennert's business empire has been the subject of considerable scrutiny and controversy, most notably concerning the environmental and social record of Renco Group's subsidiaries. His ownership of the Doe Run Company, which operated a lead smelter in La Oroya, Peru, led to widespread allegations of severe environmental pollution and adverse health impacts on the local population. These issues resulted in multiple lawsuits, including claims of human rights abuses and environmental damage, drawing international criticism regarding Renco's corporate responsibility. In the 1990s, Rennert faced an SEC investigation related to junk bond dealings with Drexel Burnham Lambert, resulting in a fine and a temporary bar from the securities industry. Additionally, Rennert is known for his opulent 62-acre estate, Fair Field, in Sagaponack, New York, which is one of the largest private residences in the United States and has been a point of local contention due to its scale. Forbes estimated his net worth at US$3.8 billion as of November 2024.