Katharine Rayner net worth: Katharine Rayner is an American billionaire heiress who has a net worth of $6 billion. Katharine Rayner is best known for being the daughter of Anne Cox Chambers and the granddaughter of James M. Cox, a newspaper publisher. In 2015 Katharine Rayner received an equal share of 49% of her mother’s share in Cox Enterprises which was distributed among Katherine, her sister Margaretta Tayler, and her brother James Cox Chambers. Cox Enterprises is a privately held conglomerate that owns television stations, newspapers, and radio stations as well as Cox Communications, AutoTrader.com, Manheim Auctions, Valpak, Kelley Blue Book, and more. In 2017 they had a revenue of $20 billion.