Supplementary Materials for: The ICANN-Accredited Registrar Population, 2018–2026: A Longitudinal Measurement Study

Data and pipeline for the paper "The ICANN-Accredited Registrar Population, 2018–2026: A Longitudinal Measurement Study". The package contains nine year-end revisions of the IANA Registrar IDs registry (2018 to 2026, last commit of each year in the public mirror larseggert/iana-assignments, commit identifiers in commits.csv), the ICANN accredited registrar list of 16 September 2026, the grouping rule set (consolidation_rules-v1.1.yaml from the transaction pipeline, Version 1.1, DOI 10.5281/zenodo.21430865, plus one added name pattern), the HTTP redirect table resolved on 16 September 2026, six Python scripts and a runner. One command reproduces all twelve result tables, six under the main grouping rule and six under a name-stem variant for IDs no longer listed, without network access; CHECKSUMS.sha256 and REPRODUCTION.log document a run from a fresh clone. Results: accredited IDs 2,463 (2018) to 3,322 (September 2026); 1,060 entries, of which 875 extend a group already accredited, and 185 belong to 183 groups not seen before; 201 exits; groups with an accredited ID 691 to 673 under the main rule and 672 to 673 under the variant. Version 1.0.4 corrects one sentence in the README; 1.0.3 fixes the variant group keys and adds the group flow checks; 1.0.2 adds the variant; 1.0.1 adds the group balance per year.