The dataset ranks 100 assignees by patent family count, with the leader holding 126 records against a fifth-place figure of 39 and a tenth-place figure of 27. The top five combined account for 23.9% of all 1,439 records in scope, and the top ten reach 35.2%, showing a steep concentration at the very top followed by a long tail of smaller filers. This is a ranked list of assignees returned by the data endpoint, not an exhaustive census of every company active in subsea engineering.

Filing peaked in 2019 at 111 records and has fallen since, with 2021's 70 filings dropping 77% to 16 by 2024. That said, 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 the field going cold. The more defensible read is that claim space around established subsea designs has become denser, which naturally slows the pace of new filing.

E21B, the classification for earth and rock drilling, appears on 54.8% of the 1,439 records in scope, making it by far the largest technical category. B63B (ships and marine vessels) and F16L (pipes and pipe fittings) follow at 11.7% and 10.8% respectively, with smaller shares in corrosion protection, geophysical surveying, material testing and hydraulic machinery. Because a single record can carry multiple classifications, these figures should be read as a share of all records, not as mutually exclusive categories.

US6481504B1 covers a flowline connector with two mating portions, one mounted to subsea equipment such as a wellhead and the other attached to a flowline end, using guides that allow pivoting into axial alignment during connection. It is one of the five most-cited records in this corpus, cited 139 times, and was granted to FMC Technologies in 2002. Its guided-pivot connection mechanism is a specific mechanical claim, not a broad category claim, so it constrains designs that use a similar guide-and-pivot make-up approach rather than blocking flowline connectors generally — a full claim-by-claim reading is needed before relying on that distinction.

Relative to the dense claim coverage in drilling-adjacent connector and accumulator hardware, areas such as riser motion sensing, corrosion-resistant coatings for subsea structures, retrievable processing module interfaces and hydraulic power take-off systems show comparatively lower filing density in this dataset. These are not guaranteed clear paths, since the underlying classifications still carry meaningful filing volume, but they carry less concentration among a handful of dominant assignees. A focused prior-art search within each specific sub-area is still necessary before drafting claims.