The dataset's leader holds 288 records, with the top five ranked assignees together accounting for 691 records, or 37.1% of the 1,862 records in scope. The ranking runs to 100 companies, so ownership is concentrated at the top but extends through a long tail of smaller filers, national oil companies and service providers. Anyone assessing competitive position should look at both the leader's individual share and the combined top-five and top-ten figures, since a single dominant filer does not mean the rest of the field is empty.

Filing peaked at 111 records in 2017 and the most recent complete comparison, 2021 against 2024, shows a decline from 38 to 25 records, a 34% drop. However, publication typically lags filing by around eighteen months, so 2025 and 2026 figures in any dataset are still incomplete and should not be read as confirmation of continued decline. The honest read is that activity has cooled from its mid-2010s peak, not that it has stopped.

Earth and rock drilling and wells, IPC class E21B, appears in 84.9% of the 1,862 records in scope, making it by far the dominant classification. Pipes and fittings, marine vessel integration, condensation polymers and valve mechanisms each account for under 5% of records. That gap between the dominant class and everything else suggests core well and tree mechanics are heavily claimed, while adjacent materials and integration approaches are comparatively less contested.

The United States leads with 377 filings, followed by the United Kingdom at 320 and the WIPO PCT route at 195. Europe, Australia and Norway each carry meaningful volumes as well, reflecting the concentration of subsea development off the North Sea, Gulf of Mexico and Australian coasts. A filer targeting global coverage in this space should expect the US, UK, EPO and PCT routes to carry most of the competitive activity worth tracking.

US11768976B2, filed by China University of Petroleum (East China) and published in 2023, describes a re-prediction method for subsea tree condition monitoring that combines a digital twin, a degradation re-prediction model and a remaining-useful-life calculation, using Kalman filter and Bayesian network techniques. It sits in the condition-monitoring and predictive-maintenance layer rather than the core mechanical tree assembly, so it is unlikely to block conventional valve or connector designs. Anyone building predictive maintenance software for subsea trees using similar Kalman-filter-plus-Bayesian-network architecture should review its claims closely before proceeding.