The dataset ranks 100 assignees by record count, with a single leader holding 175 of the 705 records in scope, well ahead of the fifth-ranked holder at 25 and the tenth-ranked holder at 18. The top five assignees together account for 44.4% of all records, and the top ten account for 58.4%. That steep drop-off from leader to fifth place means the field is best described as concentrated at the top with a long tail of smaller filers, rather than evenly split among a handful of comparable players.

Filings peaked at 71 in 2017 and fell to 3 by 2024, an 84% drop from the 2021 level of 19 filings. This pattern tracks the broader offshore drilling capital cycle, where new-build rig orders and associated hull engineering work slowed considerably after the mid-2010s downturn in oil and gas capital spending. It is worth noting that 2025 and 2026 figures are still incomplete because publication lags filing by roughly 18 months, so the true 2025 filing level will only become clear later.

The scope combines vessel-type terms — semisubmersible drilling unit, drillship, column-stabilised unit — with specific engineering mechanisms: heave response, variable deck load, ballast control systems, station keeping, moonpool design and pontoon buoyancy. In IPC terms, E21B (earth and rock drilling) appears on 73.8% of the 705 records and B63B (ships and marine vessels) on 43.1%, showing most filings claim both a drilling function and a hull or vessel structure together. Smaller classes covering pipe fittings, fluid control, propulsion, auxiliaries and pumps each appear on 5.1% or fewer records, marking narrower auxiliary-system claims.