On 4 October 2026, Elon Musk posted three short lines on X that racked up millions of views within hours. His message: stop saying AI, start saying SI, short for superintelligence. For anyone building in this space, that's a change in vocabulary worth paying attention to. For .si, Slovenia's two-letter domain, it could be a turning point.
What Elon Musk posted
Post on X · Oct 4, 2026
No more AI
SI
It’s better
— Elon Musk (@elonmusk) October 4, 2026 · View on X →
He followed up in the same thread with "It always was", alongside a photo of Superintelligence: Paths, Dangers, Strategies, Nick Bostrom's 2014 book about minds that outthink humans.
Reply on X · Oct 4, 2026 · with a photo of Bostrom’s Superintelligence
It always was
— Elon Musk (@elonmusk) October 4, 2026 · View on X →
Then came the reply that got everyone talking. An X user asked whether the company could be renamed to "SpaceXSI". Musk answered:
Reply on X · Oct 4, 2026 · to a user asking about a “SpaceXSI” rename
Yes, we will make that change
— Elon Musk (@elonmusk) October 4, 2026 · View on X →
NoteFor now this is a reply on X, not an official announcement. SpaceX and xAI combined into one company in February 2026, which is why a "SpaceXSI" name makes sense. We'll update this post if anything official follows.
Superintelligence has been Musk's word for a long time
The "It always was" reply makes sense when you look at the history. Musk has been talking about superintelligence for over a decade.
[TIMELINE] MUSK ON SUPERINTELLIGENCE · 2014–2026
Superintelligence has been Musk’s word for over a decade
-
The warning
Bostrom’s book
Recommends Superintelligence on Twitter and warns AI is
potentially more dangerous than nukes.
CBS News -
xAI
xAI launches
Says it will compete with OpenAI to reach artificial superintelligence. Fortune
-
The merger
SpaceX buys xAI
The deal values the combined company at about $1.25 trillion. Yahoo Finance
-
Now
“No more AI. SI.”
Posts
It’s better
and says yes to a SpaceXSI rename in the replies. X
AI vs SI: what's the difference?
"AI" covers everything from a spam filter to a chatbot. Researchers usually split it into three levels, and superintelligence is the last one.
[LEVELS] AI VS SI
From narrow AI to superintelligence
- ANI Narrow AI One job at a time
- AGI General AI Human level
- SI Superintelligence Beyond the best humans
Narrow AI (ANI)
Good at one job: recommending videos, translating text, playing chess. This is most of what we use today.
General AI (AGI)
As capable as a person across most tasks: reading, reasoning, planning, learning new skills without being retrained.
Superintelligence (SI, or ASI)
Smarter than the best humans in almost every field, including science, strategy and invention. This is the level Bostrom's book describes, and the one Musk now wants the industry to name directly.
Why .si could become the next .ai
A few years ago, .ai was just the country domain of Anguilla, a small Caribbean island. Then AI took off, and .ai became the default address for AI startups because the two letters said exactly what the company did.
.si is in the same position today. It is Slovenia's country domain, run by Register.si (ARNES) since 1992. It's two letters, easy to say, and now it spells the word one of the most-followed people on the internet wants everyone to use.
That's why a name like thinker.si reads as "Thinker Superintelligence", and starship.si reads like it came from the same company that builds rockets.
A fair caution: one post doesn't make a trend, and .ai took years to become standard. But if "SI" does catch on, the short, real-word .si names will be the first to go, just as they were with .ai.
SI-ready .si domains for sale right now
These premium names are listed on BuySiDomain. Each one links to the seller's page, where you can buy it with Spaceship escrow. Monthly payments or lease-to-own may be available on some names.
- starship.siFor anything space or launch-relatedBuy
- brainiac.siA superintelligent assistant brandBuy
- thinker.siResearch or reasoning modelsBuy
- predict.siForecasting and analyticsBuy
- superapp.siAn all-in-one SI productBuy
- birth.siA launchpad for new venturesBuy
- hyperdrive.siSpeed, compute, infrastructureBuy
- agentium.siAI agents and automationBuy
Domains marked ‘Listed by PremiumDoms.io’ are sold by PremiumDoms.io. Purchases, payments, and transfers are handled entirely on their website under their terms. BuySiDomain.com only displays these listings and is not a party to the sale.
Frequently asked questions
What does SI mean?
SI stands for superintelligence: an intelligence that is far smarter than the best humans in almost every field. It's also called ASI (artificial superintelligence).
Did Elon Musk really say to use SI instead of AI?
Yes. On 4 October 2026 he posted "No more AI / SI / It's better" on X, then followed up with "It always was" and a photo of Nick Bostrom's Superintelligence.
Is SpaceX being renamed to SpaceXSI?
Musk replied "Yes, we will make that change" when a user asked. As of 4 October 2026, that's a reply on X, not an official company announcement.
What is a .si domain?
.si is Slovenia's country code domain, managed by Register.si (ARNES). Because it reads as "SI", it's a natural fit for superintelligence projects, the way .ai became the default for AI.
Where can I buy a .si domain?
Use the .si availability checker to see if a new name is free, or browse premium .si domains already for sale. New to .si? Start with our .si domain guide.
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