1947 Holly Corporation was originally incorporated under the name General Appliance Corporation.
1949 Frontier Oil Corporation was originally incorporated under the name Wainoco Oil Corporation, which was primarily an oil and gas exploration company with production in Canada and the U.S.
1952 General Appliance Corporation changed its name to Holly Corporation to broaden its interests into oil production.
1955 Holly Corporation was listed on the American Stock Exchange (AMEX) and focused on the oil and gas exploration industry while income was mainly from real estate sales and interest.
1969 Holly purchased Navajo Refining Company in Artesia, NM from Continental Oil Company.
1972 Holly moved its home office to Dallas, TX from Azusa, CA.
1977 The Navajo Refinery eclipsed real estate as the major source of revenue for the company.
1981 Wainoco listed on the New York Stock Exchange (NYSE: WOL).
1982 Holly was included in the Fortune 500 list of largest U.S. industrial corporations.
1991 Wainoco purchased Frontier Oil Corporation, whose primary asset was a crude oil refinery located in Cheyenne, WY.
1992 Wainoco had three operating units: U.S. Oil and Gas, Canadian Oil and Gas, and Frontier Oil.
1995Wainoco sold U.S. operations in exploration and production due to lack of scale.
1997 Wainoco sold Canadian assets to pay down corporate debt and concentrated entirely on refining operations.
1998 Wainoco changed its name to Frontier Oil Corporation (NYSE: FTO) to reflect the change in corporate strategy.
1999 Frontier purchased the El Dorado, KS refinery from the Shell-Texaco joint venture, Equilon, quadrupling the company’s refining capacity.
2003 Holly purchased the Woods Cross, UT refinery from ConocoPhillips.
2004 Holly Energy Partners was formed and listed on the New York Stock Exchange (NYSE: HEP). Holly changed its listing from the AMEX to the New York Stock Exchange (NYSE: HOC).
2005 Holly was named as a “Best Managed Company” by Fortune magazine.
2007 Frontier was ranked in the top ten for “Total Return to Shareholders” and “Revenues per Employee” by Fortune magazine.
2009 Holly acquired the Sunoco and Sinclair refineries in Tulsa, OK, doubling the company’s refining capacity and number of employees.
2011 Holly and Frontier completed a merger of equals and changed name to HollyFrontier Corporation (NYSE: HFC).