Filing in this space is concentrated: the five leading assignees together hold 2,416 of the 5,545 records in scope, or 43.6% of the field, with the single leading assignee alone accounting for 991 records. That leaves a long tail of smaller filers below tenth place, which held 132 records. Anyone entering this space should expect the top-of-table names to already cover broad architecture, and should look for room in narrower mechanisms rather than trying to out-file the leader on core claims.

Filing peaked at 383 records in 2022 and has since declined to 231 in 2024, a -33% move from the 2021 count of 343. That is the most recent trend that can be treated as reliable, since publication lags filing by roughly 18 months and the 2025-2026 figures in this dataset are still filling in. The honest read is a field past its filing peak rather than one still accelerating, though it is too early to call the newest years a continued decline.

US20150326545A1, assigned to Apple and published in November 2015, describes securely rotating keys for an issuer security domain of an electronic device: an electronic device receives encrypted issuer data, decrypts it with a first key stored in the issuer security domain of its secure element, and stores a second key based on that decrypted data. This is a key-management mechanism inside the secure element rather than a claim on the secure element hardware itself, so it constrains how issuer credentials are rotated post-provisioning, not whether a device can carry a secure element at all. Anyone designing a competing key-rotation flow for issuer security domains should read its specific claim language closely before assuming a workaround.