It is known that petroleum storage tankers have purchased gasoline in Saudi Arabia, where the price is low because it is heavily subsidized by the government, and then immediately taken it to Abu Dhabi to sell at a higher price. This is an example of ? Note: This is illegal but it happens. The tankers pretend they are moving petrochemicals (which is legal to export from Saudi Arabia). Backwardation Quality basis ectrisk Arbitrage Calendar basis risk