Also called thick WHOIS · thin WHOIS · thick registry · thin registry
Thick vs. thin WHOIS, explained
New gTLD registries were set up as thick registries. The main thin ones are .com and .net, both run by Verisign. ICANN adopted a policy in 2014 to move them to the thick model. After the EU's GDPR took effect, its board deferred enforcement in 2019, and the Registration Data Policy in force since August 21, 2025 requires registrars to pass registrant contact data to a registry only where a legal basis and a data processing agreement exist. A registry lookup for a .com name today returns the registrar, dates, status and nameservers, and nothing about the owner.
For an investor, the difference shows when you research or buy a name. Owner details for .com sit with the registrar, and much of that data is now redacted, so contact usually goes through the registrar's relay form or a marketplace listing. Lookups now run on RDAP, which replaced WHOIS as the definitive source for gTLD registration data on January 28, 2025. Historical WHOIS records from data providers can still show past owners, which helps with due diligence and with documenting when you acquired a name.
Example. Because .com is a thin registry, the registry lookup showed only the registrar, dates and status, so the buyer contacted the owner through the registrar's relay form.
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Education, not financial, legal or tax advice. Domain investing is speculative and most domain names never sell. Read the disclaimer.