HF Sinclair 8-K Holly Closes Sale of Montana Refinery Assets to Connacher

Exhibit 99.1

HOLLY CLOSES SALE OF MONTANA REFINERY ASSETS TO CONNACHER

DALLAS, TX March 31 — Holly Corporation (NYSE: HOC) announced today the closing of the divestiture of the assets of Montana Refining Company, a Partnership, to a subsidiary of Connacher Oil & Gas Limited (TSX: CLL) of Calgary, Alberta, effective at 11:59 PM, March 31, 2006. Subject to certain closing adjustments, the purchase price for the assets including inventories is approximately $55 million and consists of cash and 1,000,000 shares of Connacher common stock.

ABOUT HOLLY

Holly Corporation, headquartered in Dallas, Texas, is an independent petroleum refiner and marketer that produces high value light products such as gasoline, diesel fuel and jet fuel. Holly operates through its subsidiaries a 75,000 barrels per day (“bpd”) refinery located in Artesia, New Mexico and a 26,000 bpd refinery in Woods Cross, Utah. Holly also owns a 45% interest (including the general partner interest) in Holly Energy Partners, L.P.

The following is a “safe harbor” statement under the Private Securities Litigation Reform Act of 1995: The statements in this press release relating to matters that are not historical facts are “forward-looking statements” within the meaning of the federal securities laws. These statements are based on our beliefs and assumptions using currently available information and expectations as of the date hereof, are not guarantees of future performance and involve certain risks and uncertainties, including those contained in the company’s filings with the Securities and Exchange Commission. Although the company believes that the expectations reflected in these forward-looking statements are reasonable, we cannot assure you that our expectations will prove correct. Therefore, actual outcomes and results could materially differ from what is expressed, implied or forecast in these statements. The forward-looking statements speak only as of the date made, other than as required by law, and we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

FOR FURTHER INFORMATION

Stephen J. McDonnell, Vice President and Chief Financial Officer
M. Neale Hickerson, Vice President, Investor Relations

Holly Corporation
214/871-3555

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