The Indicator explores the origins of the petrodollar system, which emerged from the 1973 oil shock and a 1974 agreement between the U.S. and Saudi Arabia. Historian David White explains how pricing oil in dollars and recycling profits into U.S. Treasuries cemented the dollar’s reserve status. The episode examines current challenges to this regime, including China’s push for yuan-denominated trade and Iran’s recent use of yuan for tolls, and discusses the potential economic impacts if the system weakens.