Sam Altman’s Startup Portfolio: 14 Companies Backed by the OpenAI CEO

The overnight success of ChatGPT in late 2022 made Sam Altman, the CEO of OpenAI, the public face of A.I. But a lesser-known aspect of Altman’s career is his long-standing role as a prolific angel investor in early-stage tech startups. Before co-founding OpenAI with Elon Musk in 2015, Altman spent eight years leading the startup incubator Y Combinator from 2011 to 2019, during which he oversaw 280 investments across a wide range of startups.

Altman continued backing many of these companies with his own wealth after departing Y Combinator. As of June 2024, he had invested in nearly 400 companies, according to an analysis of company filings by The Wall Street Journal.

Although OpenAI is currently valued at a staggering $300 billion, Altman has stated he holds no equity in the company and receives only a modest annual salary of about $76,000. This makes it difficult to determine his overall net worth. Forbes estimates the value of Altman’s equity stakes in the companies he has backed to be around $2 billion. According to the Wall Street Journal, he finances many of these investments with loans from JPMorgan Chase.

Here are 14 Altman-backed companies that are valued at over $100 million:

Reddit: social media

• Founded in: 2005
• Market cap: $27 billion
• Altman’s first investment: 2014
• Altman’s role: former board member

Under Altman’s leadership, Y Combinator became a significant early backer of Reddit. In 2014, Altman led Reddit’s $50 million Series B funding round that valued Reddit at half a billion dollars. Y Combinator continued its support by participating in the company’s $200 million Series C round in July 2017, which raised Reddit’s valuation to $1.8 billion.

After leaving Y Combinator, Altman personally invested $50 million in Reddit’s Series E round in 2021, pushing its valuation to $10 billion. Reddit went public in March 2024. Since then, its market value has climbed to nearly $27 billion. Altman served on Reddit’s board from 2014 until January 2022. The company was originally founded in 2005 by Steve Huffman and Alexis Ohanian.

Neuralink: brain-computer interface

• Founded in: 2016
• Valuation: $9 billion
• Altman’s first investment: 2021
• Altman’s role: investor

Altman joined as an investor in Elon Musk’s brain implant startup Neuralink in July 2021, participating in the company’s $205 million Series C funding round. Neuralink is developing a wireless implantable device designed to connect the human brain directly to computers. The startup was most recently valued at $9 billion following a Series E round in May 2024.

Helion Energy: nuclear fusion energy

• Founded in: 2013
• Valuation: $5.4 billion
• Altman’s first investment: 2015
• Altman’s role: investor

Helion Energy is developing what it hopes will be the world’s first fusion power plant by 2028. The company has become a cornerstone of Altman’s investment portfolio. In 2021, Altman invested $375 million in Helion’s Series E round, his largest personal investment to date, when the company was valued at $2.5 billion. In January 2024, Altman and a group of investors invested an additional $425 million in a Series F round, bringing Helion’s valuation to $5.4 billion. David Kirtley, Helion’s co-founder and CEO, told GeekWire that Altman has remained deeply involved in the company’s “hyper growth,” pushing it to move faster and test more aggressively.

Coalition: insurance and cybersecurity 

• Founded in: 2017
• Valuation: $5 billion
• Altman’s first investment: 2018
• Altman’s role: investor

Coalition, a San Francisco-based cybersecurity insurance provider, offers tools and policies to help companies defend against cyber threats. Altman participated in its $10 million seed round in 2018. The company, founded in 2017 by Joshua Motta and John Hering, reached a $5 billion valuation after its Series F round in 2022.

Asana: productivity management

• Founded in: 2008
• Valuation: $3.37 billion
• Altman’s first investment: 2016
• Altman’s role: investor

asana, a work management platform designed to help teams organize and track tasks, also counts Altman as a major early backer. He led the company’s $50 million Series C round in March 2016 and later participated in its $75 million Series D in January 2018. Asana was founded by Dustin Moskovitz, one of Facebook’s co-founders.

Wave Mobile Money: fintech

• Founded in: 2018
• Valuation: $1.7 billion
• Altman’s first investment: 2021
• Altman’s role: investor

Wave Mobile Money is a fintech startup focused on expanding access to financial services across Africa through mobile apps for money transfers and borrowing. In September 2021, Altman participated in the company’s $200 million Series A round, which brought its valuation to $1.7 billion. Wave was founded by Drew Durbin and Lincoln Quirk, who previously launched the remittance startup Sendwave before selling it to WorldRemit.

Patreon: content creation

• Founded in: 2013
• Valuation: $1.2 billion
• Altman’s first investment: 2014
• Altman’s role: investor

Patreon, a platform that enables creators and artists to offer subscriptions and sell digital products directly to fans, also attracted early backing from Altman. In 2014, he and a group of investors raised $15 million in Patreon’s Series A round. The platform’s valuation peaked at $4 billion in 2021 before dropping 70 percent to around $1.2 billion. Patreon was co-founded in May 2013 by Jack Conte and Sam Yam. Notably, Yam previously worked with Altman on the social networking app Loopt, which Altman co-founded with Nick Sivo in 2005.

Hermeus: supersonic aviation

• Founded in: 2018
• Valuation: $538 million
• Altman’s first investment: 2022
• Altman’s role: investor

Hermeus is a defense technology company aiming to develop the world’s fastest supersonic jets. Altman was a lead investor in the company’s $100 million Series B round in March 2022. Following a subsequent funding round in 2024, Hermeus reached a valuation of $538 million, according to Forge Global.

Rescale: cloud software

• Founded in: 2011
• Valuation: between $500 million and $1 billion
• Altman’s first investment: 2012
• Altman’s role: investor

Meter: internet infrastructure

• Founded in: 2015
• Valuation: $365 million
• Altman’s first investment: 2015
• Altman’s role: investor

Meter provides companies with reliable network infrastructure by integrating hardware, software and operational support. Altman has invested in Meter three times. He led the company’s $4 million seed round in December 2015 and participated in a $38 million Series B round in May 2022. He later co-led another $35 million Series B round alongside Lachy Groom, a solo tech investor and former Stripe executive. That round brought Meter’s valuation to $356 million.

Alt: sports card trading

• Founded in: 2020
• Valuation: $325 million
• Altman’s first investment: 2021
• Altman’s role: investor

Alt is an alternative asset platform that lets users trade and store sports cards. Altman participated in the company’s $75 million Series B round in November 2021, which valued the startup at $325 million.

Oklo: nuclear energy

• Founded in: 2013
• Valuation: $300 million
• Altman’s first investment: 2014
• Altman’s role: former chair

Oklo is another nuclear energy startup currently building a commercial power plant in Idaho, designed to operate for up to 10 years without refueling. It was one of the earliest companies backed by Altman during his time at Y Combinator, where he invested $120,000 in its 2014 seed round. A Series B round in 2021 brought Oklo’s valuation to $300 million. In May 2024, the company raised over $300 million by going public through a reverse merger with AltC Acquisition Corp, a SPAC backed by Altman. He stepped down as Oklo’s chair in April to focus on potential partnerships between the company and OpenAI. Oklo was founded in 2013 by Caroline Cochran and Jacob DeWitte.

Humane: software and hardware

• Founded in: 2018
• Valuation: $116 million
• Altman’s first investment: 2020
• Altman’s role: investor

Humane developed the A.I. Pin, a wearable virtual assistant. Altman invested in the company three times: leading its $30 million Series A in 2020 and joining its $100 million Series B and C rounds in 2021 and 2023. In February 2024, Humane sold all assets to HP for $116 million, ending A.I. Pin sales. Co-founder and former CEO Bethany Bongiorno now serves as a senior vice president at HP.

Apex: cybersecurity

• Founded in: 2023
• Valuation: $105 million
• Altman’s first investment: 2024
• Altman’s role: investor

Apex is an Israeli cybersecurity startup helping companies mitigate A.I. risks. Altman joined a group of investors in a $7 million seed round in 2024. In May, the company was acquired by Tenable at a $105 million valuation. Founders Matan Derman and Tomer Avni told Globes they continue to consult with Altman.