News

Holly Corporation and Frontier Oil Corporation merge

July 1, 2011

Valued Customers and Suppliers:

We are pleased to report the merger of Frontier Oil Corporation and Holly Corporation

closed on July 1, as scheduled.

We are very excited about our combined company, HollyFrontier Corporation. To highlight some of the many reasons for this excitement:

• Increased scale: 2nd largest publicly traded independent refining company with $6+ billion market capitalization; 440,000+ bpd of crude capacity

• Increased diversity: five (5) high complexity refineries

• Differentiated product markets: Mid-Continent, Rocky Mountains, and Southwest

• Crude flexibility: Ability to process variety of sweet, sour, and heavy crude oils

• Crude access: Cushing, Canadian, Permian, Bakken, Black Wax, Niobrara

• Strong cash flow: Advantaged assets/locations generate industry leading margins

• Strong balance sheet: $1+ billion of cash

• Strong liquidity: new $1 billion credit facility

• Strong credit: BB+ Standard & Poor’s rating with many investment grade metrics