Press kit — Dark-Fleet Flag Brief Issue 01

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Quotable statistics

All figures are computed from the OFAC SDN list as of 19 May 2026 (1,480 designated vessels, 1,445 with a recorded flag).

2.3% of OFAC-designated vessels (33 of 1,445 with a recorded flag) fly a flag from a transparent public-UBO register — EU member, UK, Norway, or Iceland.

35.7% (516 vessels) fly a sanctioned-state flag — Russia, Iran, DPRK, Venezuela, Cuba, or Syria — a state-instrument flag distinct from a commercial flag of convenience.

33.6% (486 vessels) fly a classic flag-of-convenience or shell-registry flag with deliberately restricted UBO disclosure.

260 vessels fly the Panama flag — making Panama the single largest shell registry in the OFAC sanctions index, more than four times the second-place flag (Liberia, 63).

246 vessels fly the Russian flag, 156 the Iranian flag, and 73 the DPRK flag — the three largest state-instrument designations.

97.7% of OFAC-designated vessels with a recorded flag fly a flag that is either a sanctioned-state instrument, a shell registry, or an unclassified intermediate jurisdiction. Only 2.3% sit under a flag whose beneficial-ownership register is publicly queryable.

35 of 1,480 OFAC-designated vessels have no flag of record at all — typically because the flag was deregistered after designation or the vessel was last seen flying a flag-of-falsification (a flag the registry does not in fact recognise).

Methodology in 90 seconds

Each OFAC-designated vessel is bucketed by its recorded flag using the jurisdiction-tiers.ts classifier — the same module ArcNautical's vessel-dossier product uses for compliance scoring. The classifier draws on three distinctions:

Tier 1 — transparent public-UBO register. EU member states, the UK, Norway, Iceland. Beneficial-ownership data is publicly queryable by name or company number.
Tier 3 — classic flag-of-convenience. Panama, Liberia, Marshall Islands, Cook Islands, Comoros, Antigua and Barbuda, St. Kitts and Nevis, Cayman Islands, and similar registries where UBO disclosure is intentionally restricted, often delegated to private agents, and often not honoured under FATF mutual-evaluation findings.
Sanctioned-state flag. Russia, Iran, DPRK, Venezuela, Cuba, Syria — state-instrument flags whose registry sits inside the comprehensively sanctioned jurisdiction itself.

Everything else is other / unclassified — typically smaller intermediate jurisdictions or impossible flags (landlocked states, registries that do not in fact exist).

Tonnage-weighting is deliberately not used. OFAC records usable tonnage for under 4% of designated vessels, so any tonnage-weighted figure would be computed on an unrepresentative sample.

Provenance & how to reproduce

Source: US Treasury OFAC Specially Designated Nationals (SDN) list. Public, free, well-documented.

Source URL: sanctionslistservice.ofac.treas.gov/api/PublicationPreview/exports/SDN.CSV

Data as of: 2026-05-19

Parser commit: ArcNautical production screening engine (commit 003e42f)

Re-run: the dataset linked under Downloads carries every input field needed to re-run the bucketing. Anyone with the SDN.CSV file and the jurisdiction-tiers.ts module (open-sourced as part of @arcnautical/maritime-routing on GitHub) can re-derive every figure in the Brief.

Use, attribution, contact

License: Free to use in editorial coverage with attribution to ArcNautical and a link to arcnautical.com/reports/dark-fleet-flag-brief/01/. No embargo.

Editorial contact: Madhav (founder) — [email protected]. Happy to discuss methodology, share the underlying calculation, or co-write a deeper cut for a specific publication's audience.

About ArcNautical: A maritime intelligence platform building vessel risk dossiers, voyage-risk scoring, and sanctions screening tools for shipowners, P&I underwriters, and compliance teams. Independent, founder-run, India.