ChatGPT creator Sam Altman has invested in dozens of companies over the years, from Elon Musk's Neuralink to Reddit

Altman is listed as an investor in Neuralink's Series C round in July 2021, according to PitchBook.

Neuralink is Elon Musk's company that is developing technology with the goal of one day implanting it in a human brain to record and possibly stimulate activity. Musk founded the company in 2016, but it wasn't publicized until 2017 when The Wall Street Journal reported on it.

The company has demonstrated its technology in pigs, and in monkeys.

Altman is listed as an investor in Lattice's seed round in May 2016, according to PitchBook.

Lattice was cofounded and is lead by Altman's brother, Jack Altman. It's an employee management platform for people teams at different companies to improve performance, engagement, and goal-setting for employees.

Altman invested in Instacart in its Series B round in June 2014, and in its Series C round in December 2014, according to PitchBook.

Instacart is a grocery delivery and pick-up service that works with different retail stores, and connects its users with personal shoppers to do their grocery shopping for them. The company was founded by Apoorva Mehta, Brandon Leonardo, and Max Mullen.

Altman led Reddit's Series B round, in which the company raised $50 million, according to PitchBook. He also invested in Reddit's Series C round in July 2017.

Reddit is a website for discussion and sharing news that users can vote on. It was in the same Y Combinator batch as Loopt, Altman's first startup. Reddit was founded by Alexis Ohanian, Aaron Swartz, and Steve Huffman. Altman sat on Reddit's board of directors for seven years, and left in January 2022.

Altman is listed as an investor in Patreon's Series A round in June 2014, according to PitchBook. 

Patreon is a platform that lets content creators earn money through subscriptions from their fans. With a subscription, a creator's fans get access to exclusive content. Patreon was founded by Sam Yam and Jack Conte, who is the current CEO.

In July 2014, Y Combinator invested $1 million in Helion Energy's Series A round, according to PitchBook. Altman led the company's Series E round in November 2021, investing $375 million into the fusion energy company. Helion Energy raised $500 million in that round, according to PitchBook.

Helion Energy converts a form of hydrogen called deuterium into helium-3, which it says is "the ideal fuel for fusion electricity."

Altman said in an interview that Helion is "more than an investment to me," and that apart from spending time on OpenAI, he's spent "a lot of time" on Helion because he's "super excited about what's going to happen there."

Helion Energy was founded by David Kirtley, Chris Pihl, and George Votroubek.

Altman led Asana's Series C round in March 2016, according to PitchBook, in which  the company raised $50 million. He also invested in the company's Series D round in January 2018. Asana has since went public.

Asana is a work management platform to keep work teams organized with automated lists, timelines, and boards. The company was founded by Justin Rosenstein and Dustin Moskovitz, who is currently CEO.

Altman is listed as an investor in Change.org's Series C round in December 2014, and in a Series A round in May 2017, according to PitchBook.

Change.org is a website that allows people and organizations to start petitions that people around the world can sign and support. 

The company was founded by Ben Rattray and Mark Dimas.

Rescale is a cloud-based platform for engineers and computational scientists in industries like aerospace and energy to build and run simulations.

Altman invested in it four times, according to PitchBook. He's listed as an investor in its seed rounds in March 2012 and July 2015. He also invested in its Series B round in December 2018, and its Series C round in November 2021.

Rescale was founded by Joris Poort and Adam McKenzie. 

Altman invested in Codecademy's Series A round in October 2011, according to Crunchbase. 

Codecademy is an online platform with coding classes that are free. It has classes for 12 different programming languages such as Python, JavaScript, and SQL. 

The company was Ryan Bubinski and Zach Sims, who is currently CEO.

Altman invested in both the October 2020 and November 2022 seed rounds for Rewind, according to PitchBook.

Rewind is an AI-powered search engine that says it records "everything you've seen, said, or heard," to make it easier to search on your computer.

The company was founded by Brett Bejcek and Dan Siroker.

Altman invested in Rain Neuromorphics' Series A-2 and A-3 rounds in January 2021, and in its Series A1 round in January 2022.

Rain Neuromorphics builds artificial brains to enable advanced artificial intelligence development. 

The company was founded by Jack Kendall, Juan Nino, and Gordon Wilson, who is the current CEO.

Altman invested in Atmos' seed rounds in June 2019 and October 2020, according to PitchBook. He is also listed as an investor in its Series A round in November 2022.

Atmos is a real estate company that helps people custom build their home where they want while sticking within their budget and needs. It was founded by Austin Kahn, Matthew Rastovac, Trent Hedge, and Nicholas Donahue, who is currently the CEO.

Altman invested in Coco's seed round in November 2020, and was one of the lead investors in its Series A round in February 2022, according to PitchBook. Coco raised $56 million in its Series A, per PitchBook.

Coco is a robot delivery service that transports food and other goods from a store to its customers. It was founded by Brad Squicciarini and Zach Rash, who is currently the CEO.

Altman invested in ZeroDown's seed round in March 2019 and its Series A round in June 2019, according to PitchBook.

ZeroDown is a lending startup that buys homes on behalf of its customers with an all-cash offer, then gives customers up to five years to buy the house back from it, plus interest.

It was cofounded by Lakshminarasimhan Raghavan and Abhijeet Dwivedi, who is currently its CEO.

Altman invested in TrueNorth's Seed round in February 2020, and was one of its lead investors in its Series B round in December 2021, according to PitchBook. The company raised $50 million in its Series B.

TrueNorth helps truckers and people who own a small fleet of trucks run their business from one platform, and has a mission to help truckers make more money. It was founded by Sanjaya Wijeratne and Jin Stedge, who is the CEO.

Altman was a lead investor in Brinc's Series A1 round in October 2020, according to PitchBook. The company raised $2.2 million in its Series A1, according to PitchBook. Altman also invested in its Series A round in April 2021.

Brinc was founded "in response" to the 2017 Las Vegas shooting, according to its website. The company deploys drones and other technology "that benefit the community and help save lives." It was founded by CEO Blake Resnick. 

Altman invested in Campuswire's seed round in July 2021, and in its Series A round in January 2022, according to PitchBook.

Campuswire is an online platform for university students to follow announcements and discussions, as well as ask questions for their classes. It was founded by CEO Tade Oyerinde.

FarmLogs is an online platform that gives farm owners data driven insights so they could easily manage everyday operations and make profitable crop sales. The company was cofounded by Jesse Vollmar, Mark Kvamme, and Tim Streit, according to PitchBook.

Altman invested in FarmLogs' Series B round in December 2014, and its Series C round in January 2017, according to PitchBook. FarmLogs was acquired by software company Bushel in 2021.

Altman invested in seed rounds for HelixNano in December 2016 and March 2020, according to PitchBook. He then invested in its Series A round in March 2022. 

HelixNano is focused on using mRNA to make an impact on issues like COVID-19, and to make an impact on the environment. It was founded by Nikolai Eroshenko and Hannu Rajaniemi, its CEO.

Altman was one of the lead investors in Humane's Series A round in September 2020, according to PitchBook. The company raised $30 million in this round. He also invested in its Series B round in July 2021.

Humane is a hardware and software company that makes products to help people build innovative technology. It was founded by ex-Apple employees Imran Chaudhri and Bethany Bongiorno.

Altman invested in Journey Colab's seed round in October 2020, and its Series A1 round in November 2021, according to PitchBook.

Journey Colab is a biopharmaceutical company that is focused on finding and developing psychedelic therapies for addictions. It was founded by CEO Jeeshan Chowdhury.

Altman invested in Meter's Series A round in October 2020, and its Series B round in May 2023, according to PitchBook. 

Meter is a company that builds enterprise-grade internet infrastructure for businesses. It was founded by brothers Sunil Varanasi and Anil Varanasi, who is CEO.

Altman invested in Science Exchange's Series A round in April 2013, and its Series B round in March 2016, according to PitchBook.

Science Exchange is an online R&D marketplace that aims to streamline outsourcing research and development services between scientists. It was founded by Elizabeth Iorns and Dan Knox.

Altman invested in TrialSpark's Series B round in October 2018, and its Series C round in September 2021, according to PitchBook.

TrialSpark is a biotech platform that accelerates the timing of clinical trials using automation and data so patients can receive treatment faster. It was founded by Ben Liu and Linhao Zhang.

Altman invested in Nautilus Labs' seed round in February 2019, according to PitchBook. 

Nautilus Labs uses AI to improve ocean commerce efficiency.