Diesel has generally been more expensive than gasoline since 2004 due to higher production costs and taxes. This price premium widened significantly in recent years due to global refinery disruptions and low inventories. While US crude and refinery output have increased, they cannot fully compensate for global diesel supply shortages. The shift from diesel being cheaper began around 2004 with new environmental standards requiring ultra-low-sulfur diesel. This change increased refining costs and capital investments for producers. Furthermore, diesel has become a global commodity, meaning its price is heavily influenced by international demand and supply dynamics. Events like Russia's invasion of Ukraine in 2022 severely disrupted global diesel markets, pushing prices to record highs. Currently, a combination of reduced refining activity in key regions and increased global demand has tightened distillate supplies worldwide. Despite strong domestic production, US inventories have fallen as exports increased to meet this global demand. Geopolitical conflicts and export restrictions from major suppliers like China and Russia have further exacerbated the supply squeeze. Consequently, the current extraordinary price gap between diesel and gasoline reflects a critically tight global distillate market.