The other components in the list are a circuit board for managing input and output ports, a power adapter, a charging cable and a cooling system for the computer's processor. Bloomberg says the USTR sent Apple letters explaining that the company "failed to show that the imposition of additional duties on the particular product would cause severe economic harm to [Apple] or other US interests." It sounds like Apple failed to convince the agency that those particular components deserve to be exempted, even though it told the USTR that "there are no other sources for" the proprietary, Apple-designed parts.

Whether Apple's failure to secure an exemption for the five components will have an impact on the Mac Pro's pricing remains to be seen. Apple set its starting price at $5,999, and the wheels were always supposed to cost extra.