There are many successful women in business in America, so it's difficult to say who is the most successful overall. However, some of the most well-known and accomplished women in business include: Mary Barra: CEO of General Motors, the first female CEO of a major global automaker. Abigail Johnson: CEO of Fidelity Investments, one of the largest financial services companies in the world. Ginni Rometty: Former CEO of IBM, who oversaw the company's transformation into a cloud computing and artificial intelligence leader. Sheryl Sandberg: COO of Facebook, author of the bestselling book "Lean In," and a prominent advocate for women in business. Oprah Winfrey: Media mogul and founder of OWN, a cable network dedicated to inspirational programming.