The Sep 2018 List 3 announcement produces front-running into Dec 2018; the May 2019 escalation to 25% deepens China’s decline through 2019; Vietnam, the registered diversion destination, accelerates in the same months.
What the record shows
Against the donor counterfactual (world ex-China ex-Vietnam, method rule 12), China ran
+24pp above counterfactual in December 2018 (+1,147 kt of front-run cargo) and
−40pp below it by December 2019 (−2,383 kt). Vietnam accelerated from +25–31%
in spring to +40% and +48% in the exact Q4 months China cratered. The mirror image is
textbook trade diversion — and this study doubles as the positive control for the whole
atlas method.
Imports from China, % change on a year earlier. The May 2019 escalation deepens the slide to −35% by December.Imports from Vietnam, % change on a year earlier — accelerating into the exact months China falls.
What would prove this wrong
A donor pool falling in step with China would mean the "decline" was global demand, not tariffs; donors were flat to up (+5 to +10%) throughout.
Cite this
In print: “The 2019 tariff hike pushed China down and Vietnam up, in mirror image” — a pre-registered event study
by the Trimtab US Trade Ledger, ruled 2026-08-06, from US Census port records and 174,440 vessel
stays (NOAA AIS, 2018–2024) — trimtabist.com/atlas/list3-tariff-diversion For the record: Event Atlas · list3-tariff-diversion · CONFIRMED · ruled 2026-08-06
This study is a frozen artifact: the ruling and its exhibits do not change when new
data lands. If the verdict is ever revised, the revision is printed here with its reason, and the
original stays on the record.