EL DORADO, Ark.--(BUSINESS WIRE)--Murphy USA Inc. (NYSE: MUSA) is issuing an operational update in advance of executive attendance at two investor conferences in June, the Jefferies Consumer Conference on June 18th and the JP Morgan Energy, Power, Renewables, and Mining Conference on June 24th. Ahead of these conferences and investor discussions, Murphy USA is updating second quarter-to-date performance metrics based on preliminary results covering the period April 1st to May 31st: Second Quart