Across the ranked field of 100 assignees, the leading company holds 1,442 records out of 54,638 in scope, with fifth place at 827 and tenth at 446. That taper shows a real but not dominant leadership position — the top five assignees combined hold only 10.7% of all records, and the top ten reach 15.9%. Most of the corpus sits outside this ranked group, spread across a long tail of single- and low-count filers, so leadership in this field is contested rather than concentrated in one or two names.

Filing volume rose from 847 records in 2017 to a peak of 1,139 in 2022, then settled at 944 by 2024 — a -5% move from the 2021 level of 996. That is best read as a plateau after a growth phase, not a decline. Publication lags filing by roughly 18 months, so the 2025 and 2026 figures in any dataset are always going to look lower than they will once filings catch up, and should not be used to call a downward trend.

F25B, refrigeration and heat pumps, is the leading IPC subclass at 10.0% of the 54,638 records in scope — roughly three times the share of the next largest, F24F (air conditioning and ventilation) at 3.3%. Because a single record can carry several IPC classes, these shares add up to more than 100% and should not be summed together. The remaining subclasses connected to steam/thermal power, domestic heating, working-fluid materials, medical fluid devices, heat exchangers and water heaters each sit in a narrower 2-3% band, showing that filing weight concentrates in the refrigeration cycle itself rather than any single downstream application.