One assignee leads the ranked field with 277 records, well ahead of the fifth-placed assignee at 76 and the tenth at 50. The top five assignees combined account for 773 records, 26.5% of the 2,914 records in scope, so while there is a clear leader, the majority of filings sit with a long tail of universities, hospital research centres and smaller biotech firms. Anyone doing freedom-to-operate work should check both the leader’s portfolio and the wider tail, since concentration here is real but far from total.

Filing peaked in 2020 at 273 records and had eased to 179 by 2024, a -25% move over that three-year window. That decline should be read carefully: publication lags filing by roughly 18 months, so 2025 and 2026 figures in any dataset are still incomplete and understate true activity. The more useful reading is that the field has moved from a rapid build-out phase into a plateau, likely as formulation approaches converge around workable serum-free recipes.

The core class is C12N, covering microorganisms and genetic engineering techniques, present in 97.5% of the 2,914 records in scope. Beyond that base, A61K (medicinal preparations) appears in 30.2% of records, G01N (material analysis and testing) in 21.5%, and C12M (bioreactors and apparatus) in 12.6%, showing that most filings pair a culture-media claim with either a therapeutic use, an assay method, or hardware. Because records can carry multiple classes, these shares add up to well over 100% and should not be summed.