Phase 1: containerised imports from China collapse Feb–May 2020 while other origins hold (supply shock, China-specific). Phase 3: total imports surge from Aug 2020 as locked-down US consumers pivot spending to goods.
What the record shows
Imports from China fell 42% year-on-year in March 2020 while total gateway imports
fell only 10% — the collapse was China-specific, as registered. The recovery was complete by
July, and from August the boom arrived on schedule: +7%, +9%, +24%, +29%, +28% in the five months
to December, with total imports up 22% by November. March 2021’s spectacular +175% print is
the base effect off the March 2020 crater stacked on the boom — a designated artifact, not
an event (method rule 1).
Containerised imports from China through the 8 US gateways, kt/month, 2019–mid-2021. Source: US Census, mirrored (TT-008).
What would prove this wrong
Any non-China origin falling as fast as China in Feb–May 2020 would break the "China-specific supply shock" reading; none did.
Cite this
In print: “COVID hit US imports twice — a China collapse, then an everything boom” — 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/covid-two-phase For the record: Event Atlas · covid-two-phase · 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.