Sam Blackshear is the Mysten Labs co-founder who created the Move programming language, and SUI's 25 September 2026 close sits 72.51% above its 4 August close, the last before he said he was leaving for Anthropic. He'd been Mysten's chief technology officer until that August, and co-founder Evan Cheng takes the technical lead.
"I am leaving Mysten Labs and joining Anthropic to work on defensive security research" was the line he posted on 5 August 2026. SUI's lowest close after it was 0.6513 on 18 August, and by 18 September the coin stood only 17.55% above the 4 August close. Most of the gain landed in the seven bars to 25 September, so the dates line up without explaining anything.
Sam Blackshear at a Glance
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Item
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Detail
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Who he is
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Mysten Labs co-founder, Move's creator, CTO until August 2026
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Move at Meta
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Principal Engineer leading Move for Libra/Diem, nearly six years
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Mysten Labs
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Co-founded in 2021 with Diem colleagues, Evan Cheng among them
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The exit
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5 Aug 2026 post, joining Anthropic, stays on as adviser
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SUI since
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0.6927 on 4 Aug to 1.195 on 25 Sep 2026, +72.51%
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On Phemex
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SUI / USDT perpetual, up to 50x
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Who Was Sam Blackshear Before Mysten Labs?
His Sui author page credits him with a doctorate in programming languages from the University of Colorado Boulder and five years of academic research there. That research focused on static analysis for security and performance, the discipline of reading a program's code to catch its bugs before the program ever runs.
He then spent nearly six years at Meta, where the same page says he served as Principal Engineer leading the development of Move for the company's Libra/Diem blockchain initiative.
The page still introduced him as Mysten's Co-Founder and Chief Technology Officer when we opened it on 26 September 2026, seven weeks after his exit post. Its newest article under his name is dated 12 March 2026, so the title on it is stale. His technical duties went to Evan Cheng, and our profile of Sui co-founder Evan Cheng covers Cheng's years at Apple and Facebook before Mysten.
How Sam Blackshear Built the Move Programming Language
A post on the Sui blog dated 10 May 2024, on the origins of Move, says he created the language five years earlier. The same post says he designed Move specifically for writing smart contracts with a focus on safety, and it urges developers to migrate to the Move 2024 edition.
Crowdfund Insider's report on his departure puts the Meta years in the same frame. It says he first developed Move at Meta for the Libra/Diem project and has refined it for more than eight years since. The language outlived the Meta project that commissioned it, and Sui and Aptos both run on Move.
How far a flaw found on one Move chain can travel to the other is the question our Aptos and Sui safety check after the Move flaw takes up, and its answer is that the Aptos bug never reached Sui.
What the Mysten Labs Co-Founder Built on Sui
He co-founded Mysten Labs in 2021 with several former colleagues from the Diem effort, Evan Cheng among them, according to the same Crowdfund Insider report. As CTO he played a central role in designing the Sui layer-1 blockchain, and the report also credits him with work on the Walrus protocol.
Cheng runs the company as chief executive, and the two men had worked together on Diem before either of them built Sui.
His author page tracks what he shipped after Sui went live. It lists the Move Registry on 24 April 2025, the Sui Prover for formal verification on 30 May 2025 and a decentralized key server for Seal on 12 March 2026. That last one is his final post on the page.
For the chain itself, our explainer on what SUI is as a layer-1 blockchain walks through its design for scalability.
Why Sam Blackshear Left Mysten Labs for Anthropic
He announced the move in a social media post on 5 August 2026, and Crowdfund Insider reported it on 9 August with his words quoted in full. You won't find a token or a new chain in the reason he gave. The report says he framed the job around a shift in security work, where AI is changing the balance between the people who launch cyberattacks and the people who stop them.
He keeps a role at Sui as an adviser. The report says he plans to stay a close advisor to Mysten and to any Sui developers who ask for guidance. He also wants to stay involved with the Move Foundation, which the report describes as still in development.
Technical direction at Mysten passes to Evan Cheng, the co-founder and chief executive. Blackshear credited Cheng with personally recruiting much of the company's top technical talent.
Anthropic is the AI company behind the Claude models, and our profile of Anthropic CEO Dario Amodei covers the man who runs the lab Blackshear joined.
What the SUI Price Did After Sam Blackshear Left
SUI / USDT closed at 0.6927 on 4 August 2026, the last Phemex daily close before his post in any time zone. It closed at 1.195 on 25 September, a gain of 72.51%, and measured from the 5 August close of 0.6898 the gain is 73.24%.
The path ran down before it ran up. SUI slid to 0.6513 on 18 August, its lowest close since the post. Through 18 September SUI stood only 17.55% above the 4 August close, so most of the 72.51% came in the window's final week. That week took SUI to its highest close since 13 May 2026, when it finished at 1.2074. If you read the chart as a verdict on his exit, you've got to explain six slow weeks first.
The longer record puts the move in proportion. Our pull of Phemex's daily SUI / USDT closes holds 1,000 bars from 31 December 2023, and the highest close among them is 5.2896 on 4 January 2025. The 25 September close sits 77.41% below that window high, which is a high in our record and never a claim about an all-time peak.
Where SUI heads after 25 September is a forecasting question, and our Sui price prediction for 2026 to 2031 sets out the scenarios.
How to Trade SUI Futures After the Blackshear Exit
Via crypto: SUI futures on Phemex run on the SUI / USDT perpetual, live since 3 May 2023 with leverage of up to 50x. Funding is paid or received every eight hours, so you're charged or credited three times a day while you hold. Phemex also lists a SUI / USDC perpetual.
Via the AI side of his move: Phemex also lists an ANTHROPIC / USDT perpetual, live since 9 May 2026 with leverage of up to 10x. It closed at 2,029.88 on 25 September, 39.35% above its 4 August close of 1,456.64, so SUI outran it over the same window.
The exit set the start date of that window, and SUI did most of its moving in the final week of it.
Disclaimer: This article is for informational purposes only and is not financial advice. Cryptocurrency trading involves substantial risk. Always do your own research before making investment decisions.
