 DALLAS--BUSINESS WIRE--HollyFrontier Corporation NYSE: HFC the Company plans to announce results for its quarter ending March 31, 2021 on May 5, 2021, before the opening of trading on the NYSE. The Company has scheduled a webcast conference on May 5, 2021 at 8:30 a.m. Eastern time to discuss financial results. This webcast may be accessed at: An audio archive of this webcast will be available using the above noted lin 