Sam Altman

Sam Altman is an American technology executive and investor, born April 22, 1985 in Chicago. He is the co-founder and chief executive officer of OpenAI, the developer of ChatGPT and the GPT model family, and was previously president of Y Combinator from 2014 to 2019. As of May 2026, he leads the highest-valued private AI company in the world following the March 2026 close of OpenAI's $122 billion funding round at an $852 billion post-money valuation.

At a glance

• Education: Computer science at Stanford University (2003 to 2005, did not complete degree).
• Current role: Chief Executive Officer of OpenAI, since 2019 with a five-day firing in November 2023.
• Key contributions: co-founder of OpenAI (December 2015), former president of Y Combinator (2014 to 2019), founder of Loopt (2005), co-founder of Worldcoin / Tools for Humanity (2019).
• Personal investing: portfolio of more than 400 companies estimated at over $2.8 billion as of 2024, spanning fusion energy, fintech, AI infrastructure, and consumer software.
• X / Twitter: @sama
• LinkedIn: Sam Altman
• Personal site: blog.samaltman.com

Origins

Altman was born in Chicago and grew up in suburban St. Louis, where he learned to code on an Apple Macintosh his parents bought him at age eight. He attended John Burroughs School in St. Louis before enrolling at Stanford University to study computer science in 2003.

In 2005, at age 19, Altman dropped out of Stanford to co-found Loopt, a location-based social networking application for early smartphones. Loopt was part of Y Combinator's first batch in summer 2005 and was acquired by Green Dot Corporation for $43.4 million in 2012. After the sale, Altman turned to early-stage investing through Hydrazine Capital, the fund he co-founded with his brother Jack Altman in April 2012, anchored by Peter Thiel.

Career

Altman joined Y Combinator as a part-time partner in 2011 and became president in February 2014, succeeding Paul Graham. During his five-year tenure, Y Combinator funded roughly 1,900 companies and expanded through YC Research and YC Continuity. His most-cited public Y Combinator lecture, "How to Succeed with a Startup" at Startup School 2018, is the canonical Altman-on-startups talk. He was briefly promoted to chairman of YC Group before leaving in March 2019 to focus full-time on OpenAI.

OpenAI was founded in December 2015 as a nonprofit. Altman was named co-chair alongside Elon Musk, with Greg Brockman as chief technology officer and Ilya Sutskever as research director. Musk departed the board in 2018 over strategic disagreements. In 2019, the organization restructured into a capped-profit entity, OpenAI Global LLC, sitting under the original nonprofit OpenAI Inc., to enable Microsoft's $1 billion investment. Altman moved into the chief executive role at that point. ChatGPT launched in November 2022 and reached an estimated 100 million monthly users within two months.

On November 17, 2023, OpenAI's nonprofit board removed Altman as chief executive, stating he had not been "consistently candid in his communications with the board." Greg Brockman resigned the same day. Mira Murati was named interim chief executive, then replaced two days later by former Twitch chief executive Emmett Shear. By November 20, roughly 700 of OpenAI's 770 employees had signed an open letter demanding the board's resignation and Altman's reinstatement. On November 22, Altman returned as chief executive and the original board was largely replaced; Bret Taylor, the former Salesforce co-chief executive, became board chair. The episode is generally referred to as the November 2023 board crisis.

Since reinstatement, Altman has led OpenAI through enterprise expansion, the Stargate infrastructure joint venture announced in January 2025, and the March 2026 close of the $122 billion funding round.

Affiliations

• OpenAI: Co-founder and co-chair, 2015-12 to 2019
• OpenAI: Chief Executive Officer, 2019 to 2023-11
• OpenAI: Chief Executive Officer, 2023-11 to present

Notable contributions

Altman is not a research author. His contributions are organizational and product:

• Y Combinator portfolio era (2014 to 2019). Funded the cohorts that produced DoorDash, Instacart, and the early stages of Airbnb and Stripe; collective public-market value of YC alumni now exceeds $600 billion.
• OpenAI product line. Oversaw the company through GPT-3 (June 2020), GPT-4 (March 2023), the ChatGPT launch (November 2022), the o-series reasoning models (September 2024), and the GPT-5 family beginning in 2025.
• Worldcoin / Tools for Humanity. Co-founder in 2019 with Alex Blania and Max Novendstern. The project, since rebranded as World, builds biometric proof-of-personhood infrastructure using iris scanning. Blania serves as chief executive; Altman is co-founder and a director of the parent company. The project is controversial in several jurisdictions over privacy concerns.
• Public commentary on AGI. Altman is among the most quoted operators on AGI timelines, the "intelligence age," and frontier-model deployment. His blog and interviews are the primary vehicles; the Lex Fridman interview from March 2023 is the most-cited public Altman interview during the post-GPT-4 period.

Investments and boards

Altman has the most-disclosed personal investment portfolio of any frontier-lab chief executive, spanning AI infrastructure, energy, and software. The entries below are limited to AI, semiconductors, datacenters, software, and energy. Other personal holdings outside these categories are not listed.

• Helion Energy (Energy): Investor and former board chair, 2014 onwards. Largest individual investor; led $375 million of the $500 million Series E in November 2021. Stepped down as board chair in March 2026 to enable a power-supply agreement between Helion and OpenAI.
• Oklo Inc. (Energy): Former board chair, 2015 to 2025. Small modular reactor developer. Altman's AltC SPAC merged with Oklo in May 2024, taking it public on the NYSE. He stepped down as chair in April 2025 ahead of nuclear-supply discussions with AI companies.
• Reddit (Software): Investor and former board director, 2014 to 2021. Led the $50 million Series B in 2014. Held approximately 9% at the time of Reddit's March 2024 IPO, making him the third-largest shareholder.
• Stripe (Software): Investor, 2010 onwards. Reported to hold approximately a 2% stake; participated in multiple rounds across the YC and post-YC period.
• Worldcoin / Tools for Humanity (Software / AI): Co-founder and director, 2019. Biometric proof-of-personhood and digital identity protocol; raised over $250 million across rounds led by Andreessen Horowitz and Khosla Ventures.
• Humane (AI): Investor, 2018 onwards. Wearable AI Pin company. Sold its software assets to HP in 2025.
• Cruise (Software / AI): Investor (via YC), 2014. Autonomous-vehicle company acquired by General Motors in 2016 for approximately $1 billion.
• Asana (Software): Investor, 2016 onwards. Lead investor in the $50 million Series C in March 2016 and the $75 million Series D in January 2018.
• Hydrazine Capital (Software): Co-founder, 2012. Early-stage fund anchored by Peter Thiel; deployed roughly 75% of capital into Y Combinator companies.

Altman also runs a separate $75 million venture fund anchored by the University of Michigan endowment, reported by Fortune in December 2023.

Network

Altman's strongest professional partnership is with Greg Brockman, who has been at OpenAI since the founding meetings in 2015 and resigned alongside Altman during the November 2023 crisis. Brockman serves as president. The relationship with Ilya Sutskever, the third anchor of the original technical team, broke down during the November 2023 action; Sutskever voted to remove Altman, then signed the employee letter calling for his return. Sutskever left OpenAI in May 2024 and founded Safe Superintelligence the following month.

Altman's longest-standing financial backer is Peter Thiel, who anchored Hydrazine Capital and was an early mentor in the YC era. Reid Hoffman was an early OpenAI board director and a contributor to the original $1 billion pledge in 2015; Hoffman resigned from the OpenAI board in March 2023 to avoid conflicts with Greylock and his co-founding of Inflection AI. Daniel Gross and Nat Friedman, operators of the AI Grant program and the NFDG fund, are frequent co-investors across AI infrastructure and applications.

Elon Musk co-founded OpenAI in 2015 and resigned from the board in February 2018 over strategic disagreements about scale, talent retention, and Tesla AI. The dynamic became publicly adversarial in 2024 when Musk filed suit against OpenAI alleging breach of the founding mission, and again in 2025 with a follow-on suit; OpenAI countered with its own filings. Musk's xAI is now a direct competitor at the frontier tier. The trial opened in federal court in Oakland, California in late April 2026 and is expected to run roughly four weeks; Musk has requested that Altman and Brockman be removed from their roles at OpenAI as part of the relief sought.

Position in the field

As of May 2026, Altman runs OpenAI through both the largest consumer AI product (ChatGPT) and the largest private AI fundraise on record (the SoftBank-led $122 billion round at an $852 billion post-money valuation in March 2026). Industry coverage routinely identifies him as the most prominent operator-voice in mainstream AI press. OpenAI's valuation sits well above Anthropic at approximately $300 billion (March 2026), xAI at approximately $200 billion (third-quarter 2025), and Mistral AI at approximately $14 billion.

The two figures most often paired with Altman in coverage are Demis Hassabis, chief executive of Google DeepMind, and Dario Amodei, chief executive of Anthropic. Hassabis represents the corporate-research model with distribution through Google's existing surfaces; Amodei represents the closest direct competitor on capability and a commercial focus on enterprise and safety.

Outlook

Open questions over the next 6 to 18 months:

• March 2026 funding round delivery. The $122 billion headline figure includes Amazon, Nvidia, and SoftBank commitments paid in tranches. The actually-funded portion versus the announced figure is the signal.
• OpenAI corporate restructuring. Unwinding the capped-profit subsidiary under the nonprofit parent has been reported repeatedly through 2025 and 2026 without a final structure. The eventual form determines Altman's equity position, which has historically been zero.
• Musk lawsuit outcome. The Oakland trial that opened in late April 2026 includes a request to remove Altman and Brockman from their OpenAI roles.
• Worldcoin / World rollout. The US launch in April 2025 expanded the protocol's footprint, but Kenya and several European jurisdictions have restricted or paused operations over data-protection concerns.
• Helion Energy demonstration. The first OpenAI power purchase agreement, announced in March 2026, is the primary commercial milestone to watch ahead of net-electricity-positive fusion targets later this decade.

Sources

• Sam Altman. Wikipedia biographical entry; covers career, investments, and personal life.
• Removal of Sam Altman from OpenAI. Wikipedia entry covering the November 2023 board crisis day-by-day.
• 4 days from fired to re-hired: A timeline of Sam Altman's ouster from OpenAI. ABC News timeline of the November 2023 events.
• OpenAI raises $122 billion to accelerate the next phase of AI. OpenAI's official statement on the March 2026 funding round.
• OpenAI Valued at $852 Billion After Backing From Amazon, Nvidia, SoftBank. Bloomberg coverage of the March 2026 close.
• Sam Altman-backed fusion startup Helion in talks to sell power to OpenAI. TechCrunch on the Helion-OpenAI power agreement and Altman's board chair transition.
• Sam Altman steps down as Oklo board chair. CNBC on the April 2025 Oklo chair transition.
• Sam Altman's decade-old investment in Reddit is now worth over a billion dollars. Fortune on the Reddit stake history and IPO outcome.
• Sam Altman quietly got $75M from the University of Michigan for a new venture capital fund. Fortune on the new venture vehicle.
• Elon Musk and Sam Altman are going to court over OpenAI's future. MIT Technology Review on the April 2026 trial.
• The Orb Will See You Now. TIME on Worldcoin and Tools for Humanity.
• Photo: Wikipedia entry on Sam Altman, CC-BY 2.0 Steve Jennings (TechCrunch SF, October 2019).