{"classifier_version":"1.4.0","documentation":"https://rirtracker.com/api/","disclaimer":"This site independently analyzes publicly available Internet number-resource records. It is not affiliated with or endorsed by ARIN, the RIPE NCC, APNIC, LACNIC, AFRINIC, the Number Resource Organization (NRO), or any other Regional Internet Registry. Classifications and hold-expiration dates are evidence-based interpretations and do not constitute confirmation that a resource is available for issuance or transfer.","resource":"141.173.0.0/16","resource_type":"ipv4","page":"https://rirtracker.com/ip/141.173.0.0-141.173.255.255/","statistics_now":{"registry":"ARIN","status":"allocated (dated 1992-01-24)"},"current_holder":{"rir":"ARIN","org":"Pfizer Inc.","how":"ARIN's latest statistics and the latest transfer record"},"rdap_snapshots":[],"transfers":[{"id":5966,"date":"2015-09-04T17:27:38Z","type":"MERGER_ACQUISITION","source_rir":"ARIN","recipient_rir":"ARIN","source_org":"American Cyanamid","recipient_org":"Pfizer Inc.","range":"141.173.0.0/16","log":"ARIN"}],"events":[{"event_id":"85b89fcbd9456668","registry":"ARIN","report_date":"2015-09-04","source":"transfers","raw_action":"TRANSFER","raw_line":null,"resource_type":"ipv4","resource":"141.173.0.0/16","start":"141.173.0.0","end":"141.173.255.255","classification":"MERGER_ACQUISITION","classification_label":"Merger/acquisition or reorganization","confidence":"CONFIRMED","source_rir":"ARIN","recipient_rir":"ARIN","source_organization":"American Cyanamid","recipient_organization":"Pfizer Inc.","inventory_effect":"No effect on ARIN applicant inventory","inventory_effect_code":"NO_EFFECT","provisional":false,"classifier_version":"1.4.0","classified_at":"2026-10-14T00:18:23+00:00","page":"https://rirtracker.com/ip/141.173.0.0-141.173.255.255/#e-85b89fcbd9456668","report_page":"https://rirtracker.com/arin/reports/2015-09-04/","evidence_url":"https://rirtracker.com/api/v1/resources/ip/141.173.0.0-141.173.255.255.json","observed":"Merger/acquisition: American Cyanamid (ARIN) to Pfizer Inc. (ARIN)","explanation":"ARIN's transfer log records a merger, acquisition or reorganization from American Cyanamid (ARIN) to Pfizer Inc. (ARIN) on 2015-09-04 17:27 UTC. The registration changed hands; it is not a new allocation from ARIN. ARIN-Issued and ARIN's statistics don't show this change; only the transfer log records it.","evidence":[{"type":"transfer","url":"https://ftp.arin.net/pub/stats/arin/transfers/transfers_latest.json","retrieved_at":"2026-10-13T13:57:20+00:00","summary":"Transfer log: MERGER_ACQUISITION on 2015-09-04 17:27 UTC, American Cyanamid (ARIN) to Pfizer Inc. (ARIN); resources moved: 141.173.0.0/16"},{"type":"delegated_before","url":"https://ftp.arin.net/pub/stats/arin/archive/2015/delegated-arin-extended-20150903.gz","retrieved_at":"2026-10-12T20:58:00+00:00","summary":"ARIN delegated statistics 2015-09-03 (produced 2015-09-03T05:05:25+00:00), before the report: assigned (dated 1992-01-24)"},{"type":"delegated_after","url":"https://ftp.arin.net/pub/stats/arin/archive/2015/delegated-arin-extended-20150905.gz","retrieved_at":"2026-10-12T20:58:11+00:00","summary":"ARIN delegated statistics 2015-09-05 (produced 2015-09-05T05:05:28+00:00), after the report: assigned (dated 1992-01-24)"}]}],"classification_history":{"85b89fcbd9456668":[{"raw_change_id":549516,"classification_code":"MERGER_ACQUISITION","confidence":"CONFIRMED","classifier_version":"1.4.0","classified_at":"2026-10-14T00:18:23+00:00","current":1,"public_explanation":"ARIN's transfer log records a merger, acquisition or reorganization from American Cyanamid (ARIN) to Pfizer Inc. (ARIN) on 2015-09-04 17:27 UTC. The registration changed hands; it is not a new allocation from ARIN. ARIN-Issued and ARIN's statistics don't show this change; only the transfer log records it."}]},"arin_statistics_now":{"status":"allocated (dated 1992-01-24)"}}