Tariff WatchChapter 99 of the Harmonized Tariff Schedule holds temporary modifications: provisions that suspend, reduce or add to the ordinary rates in chapters 1 to 98 without altering them. Subchapter III is where the trade remedies live, and a Chapter 99 heading is what an importer reports on the entry alongside the ordinary classification.
What a heading is
A number, a scope, a rate, and a mechanism.
A subchapter III heading names the goods it reaches, in prose or by reference to a U.S. note that enumerates their provisions, and states a rate. Heading 9903.94.05, for example, covers automobile parts as provided for in subdivision (g) of U.S. note 33, and states "The duty provided in the applicable subheading + 25%".
An entry summary reports the Chapter 99 heading first and the chapter 1 to 97 classification after it, in a sequence Customs prescribes: chapter 98 provisions, then Section 301, then Section 232 or 201, then other duty and use provisions, then quota provisions.
The headings are not uniformly additive
Three mechanisms, and the difference is money.
Of the 629 heading 9903 lines in revision 17, 240 add to the Column 1 rate, 226 add nothing, and 94 state a rate that applies in lieu of the Column 1 rate under U.S. note 1 to subchapter III. Several Section 232 derivative headings work the third way, imposing a flat floor rather than an addition.
A further group operates in pairs that cap rather than add. One heading of the pair covers articles whose Column 1 rate is at or above a threshold and adds nothing; the other covers articles below it and states a flat rate in place of the Column 1 rate. The effect on the combined duty is a ceiling, not a surcharge.
Reading every Chapter 99 heading as additive overstates the duty on every affected line, which is why the mechanism is read from the duty text rather than assumed.
A heading is not evidence a duty is in force
The schedule keeps printing headings after collection stops.
Chapter 99 retains a heading after the action behind it has stopped being collected. Revision 17 still prints the IEEPA headings, including a complete reciprocal rate ladder, months after the Supreme Court held the statute does not authorize tariffs. Scope and rate can be taken from the schedule; whether the duty is being collected cannot.
Related
Elsewhere on this site.