The ranking is led by a single assignee holding 77 of the 442 records in scope, well ahead of the fifth-place holder at 19 and the tenth-place holder at 11. The top 5 assignees combined account for 50.5% of all records, and the top 10 account for 65.8%, so the field is concentrated at the top rather than evenly spread. Beyond the top 10, the ranking of 100 companies thins into a long tail of firms with only a handful of filings each, which is typically where smaller biotech and CDMO applicants sit.

Filing peaked in 2017 at 22 records and the last three-year span that can be treated as complete, 2021 to 2024, shows a drop from 15 to 7 filings, a 53% decline. Publication lags filing by roughly 18 months, so 2025 and 2026 figures are still filling in and should not yet be read as confirming a continued slowdown. Several of the historically largest filers show no recorded filings in the latest tracked year, which is consistent with a portfolio that has matured rather than one in active retreat.

Biology-side claims sit mostly under C12N (microorganisms and genetic engineering), which covers 96.6% of the 442 records, and extend into C12P (fermentation and enzymatic synthesis) and C07K (peptides and proteins), each covering roughly a third of records. Hardware-side claims covering the physical retention apparatus — filters, membranes, perfusion devices — sit under C12M, which covers only 29.9% of records. Because a record can carry multiple IPC classes, these figures should be read against the 442-record total rather than against each other, but the gap itself indicates apparatus claims are comparatively less dense.