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F-001 · published · 2026-07-28

PortWatch's Indian port-call series is unfit for publication from March 2025

The claim

The 40–49% collapse IMF PortWatch reports in Indian container port calls between mid-2025 and March 2026 did not happen in the physical trade. US customs declarations show imports from India flat to strongly up across the same window, and goods cannot reach the United States without leaving India. The series should not be cited for this period. AMENDMENT (2026-08-06) — scope precision and new evidence; original text above unchanged. The unfitness is specific to PortWatch’s vessel-CALL detection. Continued analysis of our archived mirror shows two things. First, PortWatch’s own container import and export tonnage estimates for the same ports show no collapse — they run within single digits of the prior year throughout the window — so the call series is contradicted by its companion series on the same platform, not only by US customs data. Second, the onset varies by port: the aggregate divergence begins March 2025, while JNPT’s detected calls hold near 9 per day through April and fall through May–June (7.3 → 5.3 per day) against steady export estimates of 3.2–3.8 Mt per month — consistent with a rolling detection or coverage degradation rather than a single methodology change. No claim is made against PortWatch’s tonnage series. RIGHT OF REPLY: IMF PortWatch was notified on 2026-08-06; response status: pending. This finding may be quoted with attribution to the Trimtab US Trade Ledger. For comment or the underlying data walk-through: [email protected].

Indian container-ship port calls against US goods imports from India, both indexed 6080100120140202420252026indexed 2026-02-252026-04-092026-04-092026-04-09 US goods imports from Indi Indian container-ship port n = 24 shared months · 2024-06 → 2026-05 · base window mean (2024-06→2026-05) · retrieved 2026-10-2681 policy events in window, showing the 6 most recent · 2 date labels omitted where rules crowdDrawing two series on one chart does not connect them.

How to read: both lines start at 100; a line at 70 means that record has fallen 30% from where it began. From the comparison india-calls-vs-us-imports-2026-07 · r = 0.166 — two records of the same trade should move together near 1.0; these barely do · window 2024-06→2026-05

Outcome — acknowledged by the publisher

2026-08-07Reported directly to the IMF PortWatch team by email, citing this page, before expanding our published note.
2026-08-29The PortWatch team replied in writing: “We looked into the issue and found that it stems from irregularities in the underlying AIS data source, over which we have no control.” They added a note on the AIS data irregularities affecting Mumbai Port to their public FAQ.

Their attribution — an upstream AIS source defect, not an Indian trade event — is the hypothesis this finding published. The root-cause detail (which upstream source, and why the tonnage pathway was unaffected) remains open on their side.

What would prove this wrong

Evidence that Indian container exports to destinations other than the United States fell by roughly 40% in this window while US-bound trade held up. That would make both instruments right. It requires a third source — EU or intra-Asia import statistics — which we do not yet hold.

What it changes

PortWatch's Indian series is withdrawn from every public surface here from 2025-03-01. A planned letter whose headline finding rests on this window is held, unpublished. The US customs mirror was built specifically to carry the load the PortWatch series cannot.

What it rests on

Indian container-ship port calls reported
tt002.india.container-calls · csv · provenance
status when published now withdrawn
US goods imports from India reported
tt005.india.us-imports · csv · provenance
status when published published

Source statuses are frozen at publication. If a series has since been withdrawn, that is shown — the claim was made on what was known then.

Cite this

Singh, M. "PortWatch's Indian port-call series is unfit for publication from March 2025". Trimtab finding F-001, 2026-07-28. https://trimtabist.com/trust/findings/f-001
Licence CC BY 4.0