S ir Christopher Hohn is a British billionaire hedge fund manager and philanthropist known for his aggressive activist investment style. He is the founder and managing partner of The Children's Investment Fund Management (TCI), one of London's most successful and high-profile hedge funds. He founded TCI after a successful career at the private equity firm Apax Partners.

TCI is famous for its long-term, concentrated, and often confrontational activist campaigns, taking large stakes in public companies and pushing their management for changes to improve shareholder value. The fund is also unique in its structure; it is contractually obligated to donate a portion of its profits to The Children's Investment Fund Foundation (CIFF), a major global philanthropy focused on improving the lives of children in developing countries, which was co-founded by Hohn and his ex-wife. This blend of hard-nosed activism and large-scale philanthropy makes him a unique figure in the world of finance.