The ranked leader in this corpus holds 187 records, well ahead of the fifth-place assignee at 72 and the tenth-place assignee at 41. The top five assignees combined account for 17.1% of all 2,931 records in scope, and the top ten account for 25.3%, meaning that even the most active filers together hold roughly a quarter of the field. The remaining three-quarters is spread across the rest of a 100-company ranked list plus a long tail of smaller filers, so no single company controls the space outright.

The largest concentration sits in F16B, the fasteners subclass covering bolts, rivets and related hardware, at 39.7% of the 2,931 records. B21H, covering rolling of metal articles including thread-rolling manufacture, follows at 16.8%. Smaller but present shares cover hand tools and wrenches (B25B), earth and rock drilling connections (E21B), pipe fittings (F16L), general metal working (B23P), forged metal products (B21K) and thread cutting and tapping (B23G). Because records can carry more than one IPC class, these shares add up to more than 100% of the record total.

Filings peaked in 2020 at 143 records and eased afterward, with the 2021-to-2024 window down 15%, from 73 records to 62. That decline should be read carefully: publication typically lags filing by around 18 months, so the very low counts shown for 2025 and 2026 reflect the data cut-off rather than a genuine collapse in activity. The safest read is that filing volume has come down from its 2020 high through the most recently complete year, 2024, without drawing conclusions from the incomplete years after it.