Commodity price risk
As of March 31, 2008, we have entered into costless collars to protect ourself from fuel price risks, which establish an upper and lower limit on heating oil futures prices. These transactions are in place with respect to approximately 31% of our remaining projected mainline and Express 2008 fuel requirements at a weighted average collar range of $2.29 to $2.49 per gallon of heating oil or $75.22 to $83.62 per barrel of estimated crude oil equivalent and 2% of our projected mainline and Express 2009 fuel requirements at a weighted average collar range of $2.60 to $2.80 per gallon of heating oil or $86.47 to $94.87 per barrel of estimated crude oil equivalent.
The use of such hedging transactions in our fuel hedging program could result in us not fully benefiting from certain declines in heating oil futures prices. Further, these instruments do not provide protection from the increases unless heating oil prices exceed the call option price of the costless collar. Although heating oil prices are generally highly correlated with those of jet fuel, the prices of jet fuel may change more or less then heating oil, resulting in a change in fuel expense that is not perfectly offset by the hedge transactions. At March 31, 2008, we estimate that a 10% increase in heating oil futures prices would increase the fair value of the hedge transactions by approximately $103 million. We estimate that a 10% decrease in heating oil futures prices would decrease the fair value of the hedge transactions by approximately $99 million.