Single-letter second-level domains are domains in which the second-level domain of the domain name consists of only one letter, such as . In 1993, the Internet Assigned Numbers Authority (IANA) explicitly reserved all single-letter and single-digit second-level domains under the top-level domains com, net, and org, and grandfathered those that had already been assigned. In December 2005, ICANN considered auctioning these domain names.
On December 1, 1993, the Internet Assigned Numbers Authority (IANA) explicitly reserved the remaining single-letter and single-digit domain names. The few domains that were already assigned were grandfathered in and continued to exist.
The six single-letter domains in existence at that time under .com, .net and .org were the following:
| Domain name | 1993 owner | Current owner | |
|---|---|---|---|
| i.net | INet Solutions Ltd | Saw.com[1] | |
| q.com | JG | Lumen Technologies (dba Quantum Fiber)[2] | |
| q.net | Privately owned | Privately owned[3] | |
| x.com | Marcel DePaolis & Dave Weinstein | X Corp. | |
| x.org | – | X.Org Foundation | |
| z.com | HomePage.com | GMO Internet, Inc. |
The .org TLD was subsequently reopened for single-letter domain registrations. These and selected other gTLD and ccTLD single-letter domain names currently in use, typically as shortcuts, are listed below.
| Domain name | Current user | Usage | |
|---|---|---|---|
| a.co | URL shortcut for Amazon, generally used by Amazon in SMS messages for informing purchasers of activity on an order | ||
| a.org | |||
| c.ai | |||
| c.cc | Brian Cartmell | Homepage | |
| c.im | C.IM is a general, mainly English-speaking Mastodon instance. | ||
| c.org | Change.org | URL shortcut for change.org | |
| d.gs | Dragonsayen | URL shortcut for dragonsayen.com (DraGonSayen) | |
| d.tube | DTube | Crypto-based and decentralized video-sharing platform | |
| e.gg | |||
| e.im | URL shortcut for MailTime Email Messenger | ||
| e.srl | E-Group | Official URL Of E-Group. | |
| e.sv | eMedia Holdings | IT services have been provided by eMedia since 2005, operating from Bangladesh, Germany, USA, Australia, France, Italy, Libya, Norway, UK, and Ireland. | |
| f.org | FinTech Labs | ||
| g.cn | Google's official URL shortcut to help Chinese users locate Google | ||
| g.co | Google's official URL shortcut | ||
| g.gg | Global Grid Gallery | ||
| g.gl | |||
| g.network | G.Network | London based ISP | |
| g.vu | g.vu | A URL Shortener | |
| h.plus | Unstable Reality | Homepage for the H+ research project, owned by Alessandro Perilli | |
| k.im | Kim Dotcom | URL shortcut for x.com/kimdotcom (Kim's X profile) | |
| k.tt | Citynews SpA | URL shortcut for Citinews | |
| k.vu | afraid.org | ||
| l.ink | Top Level Design | ||
| m.co | Volvo Cars | Volvo Cars' car sharing service, M | |
| m.me | URL shortcut for Messenger | ||
| m.page | mmm.page | URL shortcut for mmm.page website builder | |
| n.pr | URL shortcut for public radio network NPR | ||
| n.school | The New School | Website of The New School in Moscow | |
| o.co | URL shortcut for Overstock.com | ||
| q.digital | Q.Digital, Inc. | ||
| r.nf | LibReddit instance | ||
| s.co | URL shortcut to Snapchat's download page | ||
| s.de | Sparkasse | URL shortcut for sparkasse.de | |
| s.id | PT Aidi Digital Global | URL Shortener | |
| t.co | X Corp. | X's official URL shortcut | |
| t.ly | t.ly | URL Shortener | |
| t.me | URL shortcut for Telegram | ||
| u.ae | The United Arab Emirates' Government portal | ||
| u.to | u.to | URL Shortener | |
| v.me | URL shortcut for Visa | ||
| v.org | V Foundation[4] | ||
| w.org | Redirects to wordpress.org, has some assets for wordpress.org (under s.w.org) | ||
| w.wiki | Wikimedia Foundation | The official Wikimedia Foundation URL Shortener | |
| x.ai | xAI | Homepage URL | |
| x.company | X Development | Homepage for X Development | |
| x.team | Shortcut to X Careers, a service at X Development | ||
| y.gy | y.gy | URL Shortener and QR Code Creator | |
| y.org | Shortcut to YMCA |
Many other single-letter second-level domains have been registered under country code top-level domains. The list of country code top-level domains which have been identified to allow single-letter domains are:
Single-character non-ASCII second-level domains also exist (as seen below), also known as Internationalized domain names (IDN), these domains are actually registered as their Punycode translations (which are more than a single character) for DNS purposes. ICANN oversees a process for determining registration rules that involves wide-ranging stakeholder input and assorted Working Groups. In the case of .com domains, decisions are then implemented by Verisign, the contracted backend operator for the .com registry. The result is a list of 96,957 codepoints allowed for IDN registrations.[8] As mentioned above, some additional domains previously-registered are "grandfathered" and remain active. Many gTLDs also allow IDN registration.[9]
These 96,957 distinct IDN characters eligible for registration in .com are the essential building-blocks of languages worldwide. A single letter domain does not provide the context found in a longer string or group of words. They may appear similar to one another or to other English / Latin characters; due to this potential for confusion, browsers have restricted the characters that may be rendered and will display the restricted characters in their Punycode form. They are sometimes used as pictorial symbols and memorable links.
| Internationalized Domain Name (IDN) | Punycode Domain + TLD | Usage | Registration Date / Registrar (WHOIS entry) | |
|---|---|---|---|---|
| ꓸ.com | xn--8m8a.com | virtual collectible / digital asset | 15 July 2017 / Dynadot LLC | |
| — | — | — | — | |
| ꓮ.com | xn--ym8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| .com | xn--967c.com | 01 January 2020 / Name.com, Inc. | ||
| ᗅ.com | xn--upe.com | Former StrongestBrands URL shortcut | 26 December 2015 / Name.com, Inc. | |
| Ꭺ.com | xn--g9d.com | 18 February 2015 / Name.com, Inc. | ||
| Ậ.com | xn--zkg.com | 2-5.org | 18 April 2021 / Google LLC | |
| — | — | — | — | |
| .com | xn--b77c.com | 26 Shirts' official URL shortcut | 06 July 2019 / Name.com, Inc. | |
| .com | xn--f67c.com | |||
| — | — | — | — | |
| ꓚ.com | xn--em8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| .com | xn--c77c.com | |||
| — | — | — | — | |
| ꓓ.com | xn--6l8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| — | — | — | — | |
| ꓰ.com | xn--0m8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| .com | xn--e77c.com | erikw.com | 30. April 2018 / NameCheap, Inc. | |
| — | — | — | — | |
| .com | xn--f77c.com | Nick Davenport IQinternet.net & DBSTrust.com, UK | 29 April 2020 / GoDaddy.com, LLC | |
| — | — | — | — | |
| ꓖ.com | xn--9l8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| ꮐ.com | xn--29d.com | |||
| — | — | — | — | |
| ꓧ.com | xn--rm8a.com | virtual collectible / digital asset | 08 July 2018 / Dynadot LLC | |
| — | — | — | — | |
| ꓲ.com | xn--2m8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| .com | xn--g77c.com | 29 April 2018 / GoDaddy.com, LLC | ||
| Ī.com | xn--5ea.com | 2-5.org | 09 April 2021 / Google LLC | |
| ḷ.com | xn--mhg.com | 26 July 2017 / Internet Domain Service BS Corp | ||
| ㆲ.com | xn--3jk.com | 3 December 2022 / GoDaddy, LLC | ||
| — | — | — | — | |
| ꓙ.com | xn--dm8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| — | — | — | — | |
| ꓗ.com | xn--bm8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| — | — | — | — | |
| ꓡ.com | xn--lm8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| — | — | — | — | |
| ꓟ.com | xn--jm8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| .com | xn--q77c.com | Mahdi Taghizadeh's official URL shortcut | 16 April 2018 / NameCheap, Inc. | |
| — | — | — | — | |
| ƞ.com | xn--gia.com | virtual collectible / digital asset | 28 December 2020 / Dynadot LLC | |
| ꓠ.com | xn--km8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| .com | xn--k77c.com | 10 May 2018 / GoDaddy.com, LLC | ||
| ꚡ.com | xn--ez8a.com | NES Natural Endocrinology Specialists | 10 February 2021 / Google LLC | |
| — | — | — | — | |
| ӧ.com | xn--h6a.com | ӧ's homepage. | 09 November 2014 / Name.com, Inc. | |
| ꓳ.com | xn--3m8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| 〇.com | xn--w6j.com | Started by Cancer, Memorial | 28 February 2006 / DomainSite, Inc. | |
| .com | xn--l77c.com | Simon Young Institution.co.uk official shortcut | 28 April 2020 / CSL Computer Service Langenbach GmbH d/b/a joker.com | |
| ᩅ.com | xn--rnf.com | 11 August 2018 / Dynadot LLC | ||
| ዐ.net | xn--72d.net | NOC of the Internet | 14 January 2021 / Google LLC | |
| — | — | — | — | |
| ᴩ.com | xn--w8f.com | 25 December 2011 / Name.com, Inc. | ||
| — | — | — | — | |
| ꓣ.com | xn--nm8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| .com | xn--p77c.com | 27 April 2021 / Google LLC | ||
| — | — | — | — | |
| ꓢ.com | xn--mm8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| ꜱ.com | xn--i38a.com | 15 November 2013 / Name.com, Inc. | ||
| ꕷ.com | xn--vq8a.com | Landlord Insurance Startup Steadily URL shortcut | 04 June 2021 / Google LLC | |
| — | — | — | — | |
| ꓔ.com | xn--7l8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| ፐ.com | xn--v6d.com | Crypto Chain University's official URL shortcut | 10 December 2014 / Tucows Domains Inc. | |
| ţ.com | xn--rga.com | don Pablo donPabloNow.com official shortcut | 18 February 2021 / NameCheap, Inc. | |
| — | — | — | — | |
| ꓴ.com | xn--4m8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| .com | xn--h87c.com | 10 May 2018 / GoDaddy.com, LLC | ||
| — | — | — | — | |
| ꓦ.com | xn--qm8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| ꛟ.com | xn--508a.com | Veritas Home Buyers official URL shortcut | 10 February 2021 / Google LLC | |
| — | — | — | — | |
| ꓪ.com | xn--um8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| — | — | — | — | |
| ꓫ.com | xn--vm8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| ☓.com | xn--33h.com | Herbert R. Sim's official URL shortcut | 03 February 2005 / Tucows Domains Inc. | |
| — | — | — | — | |
| ꓬ.com | xn--wm8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| .com | xn--s77c.com | AnaptysBio's official URL shortcut | 02 March 2018 / Name.com, Inc. | |
| — | — | — | — | |
| ꓜ.com | xn--gm8a.com | virtual collectible / digital asset | 18 July 2017 / Dynadot LLC | |
| ꛉ.com | xn--j08a.com | The Trusted Home Buyer official URL shortcut | 05 May 2021 / Google LLC | |
| — | — | — | — | |
| .com | xn--e87c.com | 21 January 2018 / Google LLC | ||
| .com | xn--hu7d.com | virtual collectible / digital asset | 11 January 2019 / Dynadot LLC | |
| ㆺ.com | xn--ckk.com | iSellSquares.com Homepage | 27 February 2020 / GoDaddy.com, LLC | |
| ☺.com | xn--74h.com | Daniel Früh's official URL shortcut | 03 June 2004 / DomainSite, Inc. | |
| ツ.com | xn--bdk.com | 29 June 2019 / NameSilo, LLC | ||
| ッ.top | xn--9ck.top | virtual collectible / digital asset | 27 January 2016 / Dynadot LLC | |
| シ.top | xn--xck.top | virtual collectible / digital asset | 28 February 2022 / Dynadot LLC | |
| シ.dev | xn--xck.dev | virtual collectible / digital asset | 7 July 2023 / GoDaddy.com, LLC | |
| ꙮ.com | xn--xx8a.com | 17 October 2018 / GoDaddy.com, LLC | ||
| ʘ.com | xn--lpa.com | 17 July 2015 / Name.com, Inc. | ||
| ʢ.com | xn--vpa.com | don Pablo donPabloNow.com official shortcut | 27 February 2022 / NameCheap, Inc. | |
| ư.com | xn--yia.com | 19 August 2018 / GoDaddy.com, LLC | ||
| ॐ.com | xn--q3b.com | 19 April 2001 / Name.com, Inc. | ||
| ৬.com | xn--67b.com | Shortcut to AIEDGE | 17 September 2021 / Sav.com, LLC | |
| ৎ.com | xn--c7b.com | 10 Corp Ltd. & eMedia.Team | 14 March 2023 / NameCheap, Inc. | |
| ௐ.com | xn--0mc.com | 15 August 2020 / NameCheap, Inc. | ||
| தீ.com | xn--rlc0d.com | 17 January 2019 / Google LLC | ||
| தீ.இந்தியா | xn--rlc0d.xn--xkc2dl3a5ee0h | 06 April 2021 / Dynadot LLC |
In 2012, the Public Interest Registry (PIR) initiated Project94, in which 94 one- and two-letter domains in the top-level domain org, that had been traditionally reserved, are awarded to qualifying organizations.[10]
Only three of the 26 possible single-letter domains have ever been registered under the .com domain, all before 1992. The other 23 single-letter .com domain names were registered January 1, 1992 by Jon Postel,[11] with the intention to avoid a single company commercially controlling a letter of the alphabet. Many but not all .com two-letter domain names are among the most valuable domain names.
While it is widely believed that the domain names business.com and sex.com have been the most valuable domain name transactions, prominent two-letter domain names have only been sold after nondisclosed transactions handled by specialized broker and law firms.
The value of the LG Corp (the South Korean electronics conglomerate formerly known as Lucky-Goldstar) purchase of LG.com was never published. LG Group missed the first sale of the domain name in 2008 from the original owner the chemical company Lockwood Greene to the dot-com entrepreneur Andy Booth; Booth had used it to launch a footballing website known as LifeGames. LG Corp bought "lg.com" one year later, in 2009. Following the purchase, LG Group changed worldwide marketing to LG.com, which is now their central internet address for all countries. All national LG country domain names like "LG.de" or "LG.com.mx" redirect to "LG.com".
The value of the initially secret November 2010 Facebook purchase of FB.com was revealed two months later to be $8.5 million in cash and the rest in stocks.[12]
IG Group paid $4.7 million in September 2013 to buy IG.com.[13]
GMO Internet, Inc. purchased Z.com for nearly $6.8 million from Nissan, who previously used it for the Nissan Z series cars.[14]
With the 2005 announcement that registration of the remaining single-letter names might become available, some companies have attempted to establish a right to the names by claiming trademark rights over single letters used in such a context. U magazine, a college-oriented publication, went so far as to rebrand its website as "U.com" and apply for a trademark registration of the same phrase, before sending a letter to ICANN attempting to gain priority for the domain if it should ever become available in the future.[15]