TRACE-OU-Bench is a sequential benchmark for ontology-update decisions under evolving ontology states. It contains 620 human-reviewed ontology-update proposals generated from public U.S. SEC 10-Q filings covering 45 U.S. companies, five sectors, and 2016–2026. The public release does not redistribute SEC filing text. Instead, each record retains SEC provenance, deterministic chunk identifiers, offsets, and SHA-256 hashes. reconstruction/traceoureconstructv11.py downloads the original filing from SEC EDGAR and deterministically reconstructs the source chunk. - Train (2016–2023): 350 proposals generated against O0; reviewed Train updates build O1. - Test (2025–2026): 150 proposals generated…