https://en.wikipedia.org/wiki/Single-letter_second-level_domain https://en.wikipedia.org/wiki/Single-letter_second-level_dom... tl;dr: IANA reserved all the si

https://en.wikipedia.org/wiki/Single-letter_second-level_domain https://en.wikipedia.org/wiki/Single-letter_second-level_dom... tl;dr: IANA reserved all the single-letter domains in 1993, except for some that had been grandfathered in. All the two-letter .com domains are registered, and only available on the secondary market.