Owner Concentration

Method & caveats

• HHI is the sum of squared owner deadweight percentage shares within a segment, on the standard 0–10,000 antitrust scale, with the usual competitive / moderate / concentrated bands.
• The headline HHI stat is the DWT-weighted average of those per-segment HHIs — a summary of segment-level concentration, not a true whole-fleet market HHI (which would require every owner's share of the entire owned fleet). Read it as "how concentrated the typical segment is", not a single market-structure number.
• The “Other cargo” row is a catch-all, not a market — it pools general cargo, ro-ro, offshore, tugs, passenger and unclassified ships. An HHI over such a heterogeneous mix does not describe a real market structure, so its band label is dropped and its number muted; read it as a size bucket, not a concentration reading.
• Average age per owner is deadweight-weighted — the broker convention, where a VLCC moves the fleet age far more than a coaster.
• Fleet value sums the platform's per-vessel model valuations over the vessels that have one; the coverage percentage makes the partial valuation explicit rather than passing a biased-low total off as complete. That percentage is measured against the owner's total fleet, and only bulker / tanker / container / gas vessels carrying both a deadweight and a year-built are model-able — so an owner with general-cargo, offshore or missing-spec ships shows a structurally lower coverage that reflects “not model-able”, not “not yet valued”.
• Coverage caveat: our beneficial-owner links are partial, so this measures the structure of the known owned fleet, not the entire world fleet. It is the floor of true concentration, not the ceiling — stated, not hidden.
• Segments use the platform's single shared vessel-class classifier (gas, tanker, container, bulker, other). Distinct from the owner fleet-value leaderboard: this page is about market structure.