WARRENVILLE, Ill. — Beginning next month, IC Corporation will raise its bus prices an estimated 4 to 5 percent. Company officials said that the rising costs of copper, platinum, aluminum and palladium facilitated the need to increase the prices.

In response to the change, Michael Cancelliere, vice president and general manager of IC Corporation, said, "We continue making improvements to be as efficient as possible in our production facilities in Conway, Ark., and Tulsa, Okla., so that we don't pass the full effect of the commodity increases on to our customers."

A large percentage of a bus' material value consists of palladium and copper products, and the prices for these commodities have increased substantially — nearly 70 percent — over the last two years. Steel and aluminum prices have risen 10 percent and more than 30 percent, respectively.

The price of platinum, which is used in new 2007 emissions aftertreatment devices, has jumped up recently as well.