How much money Rockefeller have?

John D. Rockefeller, the founder of Standard Oil, is often considered the richest person in modern history. At his peak, his wealth was estimated to be around $400 billion in today's dollars, adjusting for inflation. However, exact figures can vary based on different methods of calculation and historical context. His immense fortune was primarily derived from his monopoly on the oil industry in the late 19th and early 20th centuries.