Sam Altman Companies 2026: The Full Portfolio Behind His $3.3B

Quick answer

Sam Altman is connected to more than 400 companies as an investor, founder, or chairman — but the biggest names in his portfolio are Helion Energy (fusion, stake worth roughly $1.7 billion), Stripe (payments, about $633 million), Retro Biosciences (longevity, about $258 million), and Oklo (nuclear fission, about $237 million). He co-founded OpenAI but owns none of it, co-founded Tools for Humanity (World/World ID), and runs his own investment funds. His 2026 court disclosure showed he held more than $2 billion across companies that do business with OpenAI.

The portfolio has a thesis: he funds the inputs to the future — energy, biology, identity, chips — rather than competitors to his own lab. Below is the full map of the companies that make up his $3.3 billion fortune.

OpenAI — the company he runs but doesn't own

Altman co-founded OpenAI in 2015 with Elon Musk and others, became CEO in 2019, and steered it from research lab to the company behind ChatGPT — including surviving his brief firing and reinstatement in November 2023. OpenAI officially completed a $122 billion funding round in March 2026 at an $852 billion post-money valuation, with talk of a round that could push it to $1.2 trillion or more. And his equity stake in all of it: zero.

He has confirmed the 0% figure repeatedly, including under oath in the Musk vs. OpenAI trial, and Reuters reported he received no equity in the 2025 restructuring. The arrangement traces to OpenAI's nonprofit origins and capped-profit structure. Investigations found only small, indirect holdings through vehicles like the OpenAI Startup Fund, most of which he has since sold. The richest man at OpenAI is its president, Greg Brockman (~$25.5 billion from just under 3% of the company), not its CEO.

Helion Energy — the $1.7 billion fusion anchor

Helion is the crown jewel of the portfolio and the largest single position in Altman's wealth. He backed the fusion startup in its early years, served as chairman from 2015, and in 2021 wrote a personal cheque of a reported $375 million — an almost unheard-of personal bet on a single private company. Court filings valued his stake at about $1.65 to $1.7 billion as of December 2025, roughly half his total net worth. Microsoft has an agreement tied to future electricity purchases from Helion, and the company raised additional capital in 2026 at a higher valuation.

In March 2026 Altman stepped down as chairman as OpenAI weighed a larger energy-supply deal with the company — a governance separation between his personal fortune and his employer's procurement. The bet was classic Altman: the biggest cheque went where nobody else was bidding, into fusion in 2021, years before it was fashionable.

Tools for Humanity / World — the identity moonshot

Altman co-founded Tools for Humanity in 2019 with Alex Blania and serves as chairman. The company is behind World (formerly Worldcoin) and its iris-scanning World ID system — a project aiming to build a global identity and financial network, with the orb devices that scan irises becoming one of the most talked-about (and controversial) hardware rollouts of 2023. The company was recently valued around $2.5 billion.

World sits at the intersection of everything Altman believes: identity infrastructure for an AI age, built as a for-profit company rather than a lab project. It is also a reminder of his range — the same year he was running the world's most important AI company, he was chairing a crypto-adjacent identity startup scanning eyeballs in malls.

Oklo — the fission bet he chairs

If Helion is his fusion bet, Oklo is his fission bet. Altman serves as chairman of the nuclear-fission company and helped create AltC Acquisition Corp., the SPAC that took Oklo public in 2024. His 6.65 million shares are worth roughly $237 million at recent prices, with the company valued around $6.7 billion. Between Helion and Oklo, Altman has placed two of the largest personal energy bets in tech — both on the thesis that AI's appetite for electricity will make nuclear power the bottleneck asset of the decade.

The funds: Hydrazine, Apollo, and Altman Capital

Altman doesn't just invest personally — he runs funds. He launched Hydrazine Capital in 2012 as his own early-stage vehicle, and later Apollo Projects and Altman Capital. Bloomberg pegged his fund holdings near $1.2 billion back in 2024, and the Wall Street Journal described the overall venture book at more than 400 companies. The funds are the institutional wrapper around his Y Combinator-era deal flow: the $100K angel cheques into Airbnb, Uber, Instacart, and Pinterest that became the long tail of his fortune.

The smaller-name stakes read like a tour of the 2010s and 2020s tech landscape: Cerebras (AI chips, pre-IPO stake ~$3.2M), Boom Supersonic (supersonic flight), Lattice (HR software, founded by his brother Jack), Asana (he led the 2016 Series C), Formation Bio, and Merge Labs, which he co-founded. Even the failed AI-device maker Humane appears in the book — a reminder that a 400-company portfolio includes its share of zeroes.

Reddit — the exit that already happened

One major company has left the portfolio. Altman invested tens of millions in Reddit before its 2024 IPO — and briefly served as interim CEO for eight days in November 2014 — holding 12.2 million shares worth more than $600 million at listing. By the end of 2025, court exhibits showed he had sold the entire position. The Reddit trade was arguably his cleanest public-market win: buy early, hold through the IPO, exit near the top of the AI-data-licensing boom that made Reddit's corpus valuable to labs like OpenAI itself.

The portfolio at a glance

The conflict map: $2 billion doing business with OpenAI

The 2026 court disclosure that Altman held more than $2 billion in companies doing business with OpenAI reframes the portfolio as more than a collection of bets — it is an ecosystem his own company feeds. Stripe processes OpenAI's payments. Helion may one day power its data centers. Reddit's $70-million-a-year data licensing deal (reported by Reuters for Alphabet's comparable deal, with OpenAI paying on a similar order) made his former Reddit stake an AI-adjacent asset. The structure means OpenAI's success lifts his portfolio even without a single share of the company.

That is the final irony of the companies list. The CEO who owns nothing of his company owns pieces of nearly everything around it — energy, payments, identity, chips, biology — and the machine at the center makes them all more valuable. His $76,001 salary is the only part of his income that comes from OpenAI directly. Everything else on this page is the real compensation plan.

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