Alexandre LeBrun

Alexandre LeBrun is a French entrepreneur and engineer, an alumnus of the École Polytechnique class of 1994 (X94). He is the co-founder and chief executive officer of AMI, the Paris-headquartered research company he launched in late 2025 with Yann LeCun, and a serial AI founder whose three previous ventures, VirtuOz, Wit.ai, and Nabla, each reached scale before either being acquired or transitioning to new leadership. As of May 2026, he leads AMI following its $1.03 billion seed round at a $3.5 billion pre-money valuation, announced March 9, 2026, and remains chairman and chief AI scientist of Nabla.

At a glance

• Education: Engineer's degree, École Polytechnique (X94, class of 1994).
• Current role: Co-founder and Chief Executive Officer of AMI since November 2025; Chairman and Chief AI Scientist of Nabla.
• Key contributions: founder and chief executive of three successive AI startups, VirtuOz (founded 2002, acquired by Nuance Communications in January 2013), Wit.ai (co-founded 2013, acquired by Facebook in January 2015), and Nabla (co-founded 2018); head of engineering at Facebook AI Research (FAIR) and engineering lead on the Facebook M virtual assistant from 2015 to 2018.
• X / Twitter: @lxbrun
• LinkedIn: alexandrelebrun
• Crunchbase: alex-lebrun

Origins

LeBrun is French and entered École Polytechnique in 1994 (the X94 promotion). He is referred to in French press and Polytechnique alumni materials as Alexandre LeBrun (X94).

He launched his first company, VirtuOz, in Paris in 2002, several years after graduating. The decision to bootstrap a conversational-AI startup at that point predated the modern wave of consumer chatbots by more than a decade and set the natural-language-processing track that would carry through every subsequent venture.

Career

LeBrun founded VirtuOz in Paris in 2002 as a virtual-agent platform for enterprise customer service, built on proprietary natural-language processing and machine-learning systems. PayPal, AT&T, and Symantec were among the early customers. After bootstrapping in France, he relocated VirtuOz to Emeryville, California, raised $2 million Series A in 2005 and $11.4 million Series B in 2008, and reached profitability. The company raised $20.4 million cumulatively from Galileo Partners, Mohr Davidow Ventures, and Inventures Group. Nuance Communications acquired VirtuOz on January 9, 2013, integrating the team into Nuance's Enterprise division. Terms were not disclosed.

In April 2013, three months after the Nuance acquisition, LeBrun co-founded Wit.ai with Willy Blandin and Laurent Landowski. Wit.ai built a natural-language-processing API for third-party developers to add speech and text understanding to applications without specialized AI infrastructure. The company entered Y Combinator's Winter 2014 batch and closed a $3 million seed round in October 2014 led by Andreessen Horowitz, with New Enterprise Associates and SV Angel participating. Facebook announced the acquisition on January 5, 2015, twenty-one months after the company's founding, with approximately 6,000 developers on the platform at the time. Terms were not disclosed.

LeBrun joined Facebook through the Wit.ai acquisition and remained at the company from January 2015 to September 2018. He was head of engineering at Facebook AI Research (FAIR) and led the engineering work on M, Facebook's experimental virtual assistant first announced in August 2015. M combined automated natural-language understanding with a human-in-the-loop training pipeline and was retired as a consumer product in January 2018. The Facebook period placed LeBrun directly under Yann LeCun, who had founded FAIR in late 2013, and the professional relationship established there became the basis for the AMI co-founding more than seven years later.

LeBrun left Facebook in September 2018 and co-founded Nabla in Paris later that year with Delphine Groll and Martin Raison. Nabla launched commercially in 2019 and pivoted to its current focus on AI-assisted clinical documentation for physicians. Nabla Copilot generates structured medical notes from ambient consultation audio and integrates with major electronic-health-record systems. The company raised $120 million cumulatively, capped by a $70 million Series C led by HV Capital in June 2025 with Highland Europe, DST Global, Cathay Innovation, and Build Collective participating. By mid-2025 it was deployed across more than 130 healthcare organizations and 85,000 clinicians.

LeBrun co-founded AMI with Yann LeCun in November 2025, immediately following LeCun's departure from Meta on November 19, 2025. LeCun took the executive chairman role and personally selected LeBrun as chief executive. Nabla's board approved his shift from chief executive to chairman and chief AI scientist, and the company gained "privileged access" to AMI's world-model technology under a partnership announced alongside the AMI launch. AMI's $1.03 billion seed round at a $3.5 billion pre-money valuation was announced March 9, 2026, co-led by Bezos Expeditions, Cathay Innovation, Greycroft, Hiro Capital, and HV Capital. LeBrun has stated publicly that AMI is positioned as a long-horizon research company rather than a near-term product startup, and has set up operating sites in Paris (headquarters), New York, Montreal, and Singapore.

Affiliations

• VirtuOz: Founder and Chief Executive Officer, 2002 to January 2013.
• Wit.ai: Co-founder and Chief Executive Officer, 2013 to January 2015.
• Meta AI / FAIR: Head of Engineering, January 2015 to September 2018.
• Nabla: Co-founder and Chief Executive Officer, 2018 to 2025; Chairman and Chief AI Scientist, late 2025 to present.
• AMI: Co-founder and Chief Executive Officer, November 2025 to present.

Notable contributions

LeBrun's record is anchored in operating leadership of AI companies rather than published research. The published-record signal across his career is in product systems shipped, customers acquired, and exits realized.

• VirtuOz (2002 to 2013). Pioneered enterprise virtual agents at a point when conversational interfaces were a research curiosity rather than a product category. Customers included PayPal, AT&T, and Symantec. Acquired by Nuance Communications in January 2013.
• Wit.ai (2013 to 2015). Co-founded the natural-language-understanding platform with Willy Blandin and Laurent Landowski. Entered Y Combinator's Winter 2014 batch and was acquired by Facebook in January 2015 twenty-one months after founding.
• Facebook M (2015 to 2018). Led engineering on the experimental Facebook Messenger virtual assistant. M combined automated NLU with a human-trainer pipeline and was retired as a consumer product in January 2018, though several of the underlying systems carried over into subsequent Messenger features.
• Nabla (2018 onward). Co-founded the Paris- and New York-based clinical-AI company. Nabla Copilot generates structured medical notes from ambient audio and reached 85,000 clinicians across more than 130 healthcare organizations by mid-2025.
• AMI (November 2025 onward). Co-founder and chief executive of the world-models research company alongside Yann LeCun. AMI announced a $1.03 billion seed round in March 2026 and is the highest-profile non-LLM frontier-research bet of the cohort.
• Public commentary. LeBrun has appeared on the 20VC podcast (June 2023, on open versus closed AI and EU AI policy) and the Offcall "How I Doctor" podcast (February 2026, with Yann LeCun on world models in healthcare). His public framing of AMI emphasizes long-horizon research over near-term commercial output.

Investments and boards

• Nabla (AI / Healthcare): Co-founder, Chairman, and Chief AI Scientist, 2018 to present. Privately held; $120 million in cumulative funding across three rounds. LeBrun retained the chairman and chief AI scientist roles when transitioning out of the chief executive seat in late 2025 to lead AMI.
• AMI (AI): Co-founder and Chief Executive Officer, November 2025 to present. $1.03 billion seed at a $3.5 billion pre-money valuation, announced March 9, 2026.
• Sitel Group (Software): Board member, May 2018 to mid-2020s. Appointed while still at Facebook AI Research; later rebranded as Foundever.

No public personal angel-investor activity is on record in AI, semiconductors, datacenters, software, or energy outside the founder-and-operator roles at his own companies as of May 2026.

Network

LeBrun's strongest professional relationship is with Yann LeCun, formed during the 2015 to 2018 Facebook period when LeBrun ran engineering at FAIR under LeCun's research leadership and reaffirmed in November 2025 when LeCun selected him as AMI's chief executive. Public coverage has characterized the pairing as central to AMI's founding thesis: LeCun supplying the research credential, LeBrun supplying the operating record across three previous AI exits.

The Nabla co-founders Delphine Groll (Chief Operating Officer) and Martin Raison (Chief Technology Officer) are his longest-running operating relationships and remain in place at Nabla. The Wit.ai co-founders Willy Blandin and Laurent Landowski date from 2013.

The AMI founding cohort assembled around LeCun and LeBrun includes Michael Rabbat (Vice President for World Models, longtime Meta colleague), Saining Xie (Chief Science Officer, NYU faculty and former FAIR), Pascale Fung (Chief Research and Innovation Officer), and Laurent Solly (Chief Operating Officer, former Meta southern Europe leadership).

Position in the field

LeBrun's profile combines several characteristics unusual among AI chief executives. The École Polytechnique credential places him in the French engineering establishment alongside Arthur Mensch at Mistral AI. Three operator exits across more than two decades give him a longer commercial record than most peers in the current frontier-research cohort. The FAIR period under Yann LeCun anchors the AMI founding. The dual chairmanship at Nabla and chief executive role at AMI keeps him connected to a deployed clinical-AI product while he runs a pre-product research lab.

The chief-executive role at AMI positions him as the operating counterpart to LeCun's research leadership at the most-watched non-LLM frontier-research bet of 2026. Industry coverage has framed AMI as a contrarian bet against the LLM-frontier strategy of OpenAI, Anthropic, and Google DeepMind, with LeCun's research credentials and LeBrun's operating record as the principal validating data points for the $4.5 billion post-money seed valuation.

The closest structural comparators among current AI chief executives are Arthur Mensch at Mistral AI and the senior-researcher-plus-operating-CEO pairings at Safe Superintelligence and Thinking Machines Lab. LeBrun's serial-founder background distinguishes him from peer operators whose chief-executive role is their first or second operating company.

Outlook

Open questions over the next 6 to 18 months:

• AMI's first public artifacts. Whether AMI will produce papers, models, or demonstrations during 2026, and whether they validate the world-models thesis at frontier scale. LeBrun has set the public expectation low for a near-term product release.
• Nabla and AMI partnership integration. Whether the "privileged access" arrangement produces a working clinical product built on AMI's world models, and on what timeline.
• Operating site execution. Whether AMI's four-site model across Paris, New York, Montreal, and Singapore scales without losing research coherence.
• Compute deployment. The $1.03 billion seed implies substantial compute investment. Vendor relationships, cluster scale, and timeline have not been disclosed publicly.
• Public commentary on AI policy. LeBrun has been a public skeptic of EU AI regulation through 2023 to 2025. Whether the AMI period reshapes the position is open.
• Subsequent fundraising. Whether AMI raises follow-on capital and at what valuation will indicate continued investor conviction.

Sources

• Ami Labs, led by Alexandre Lebrun (X94), set to overhaul AI, raises $1 billion. École Polytechnique alumni news on the AMI launch and LeBrun's X94 class designation.
• Yann LeCun's AMI Labs raises $1.03B to build world models. TechCrunch on the March 2026 seed-round announcement.
• Who's behind AMI Labs, Yann LeCun's 'world model' startup. TechCrunch profile of the AMI founding team and LeBrun's transition from Nabla.
• Health AI startup to benefit from $1 billion funding round for Yann LeCun's AMI. STAT on the Nabla and AMI partnership and LeBrun's dual-role transition.
• Facebook Acquires Wit.ai To Help Its Developers With Speech Recognition And Voice Interfaces. TechCrunch on the January 2015 Wit.ai acquisition and prior VirtuOz exit.
• Confirmed: Nuance Has Bought Virtual Assistant Specialist VirtuOz To Ramp Up Its Enterprise Services. TechCrunch on the January 2013 VirtuOz acquisition by Nuance.
• Nabla Raises $70M Series C to Deliver Agentic AI to the Heart of Clinical Workflows. PRNewswire on Nabla's June 2025 Series C round.
• The 'Maverick' Founder: Yann LeCun to Run AMI Labs and the CEO He Handpicked. Entrepreneur Loop profile of LeBrun's selection as AMI chief executive.
• Sitel Group Appoints Leading Facebook Artificial Intelligence Research Engineer Alexandre Lebrun to Board of Directors. PRNewswire on the May 2018 Sitel board appointment.
• Move Over LLMs! Yann LeCun & Alex LeBrun Debut AMI Labs' World Models for Healthcare. Offcall "How I Doctor" podcast with LeBrun and Yann LeCun on AMI's healthcare-AI thesis, February 2026.
• 20VC: Why No Models Today Will Be Used in a Year. 20VC podcast interview with LeBrun on open versus closed AI, EU regulation, and the Nabla operating thesis, June 2023.
• Yann LeCun's new venture is a contrarian bet against large language models. MIT Technology Review on the AMI thesis.