This is a monthly feature that highlights the top funding rounds in the U.S. for the month. Check out September’s biggest rounds.
In October, OpenAI dominated the funding landscape with a staggering $6.6 billion raise, significantly outpacing other startups. To make it onto this month’s list, companies needed to secure over $200 million, reflecting a strong investor interest in substantial deals.
Key takeaways
- OpenAI raised $6.6 billion at a $157 billion post-money valuation led by Thrive Capital, the largest round of October 2024 and bigger than xAI's $6 billion earlier that year.
- The round used convertible notes that let investors reclaim their money if OpenAI's shift from nonprofit to for-profit benefit corporation is not completed within two years.
- Backers included Altimeter Capital, Fidelity, Khosla Ventures, Microsoft, Nvidia, SoftBank and Abu Dhabi's MGX, with SoftBank's Vision Fund reported at $500 million.
- Energy was the month's second theme: Pacific Fusion raised over $900 million, X-energy about $500 million backed by Amazon, and Form Energy $405 million — all tied to powering AI demand.
- Crusoe Energy Systems, which began by using natural gas for Bitcoin mining, raised $500 million at a $3 billion valuation after pivoting to AI infrastructure.
OpenAI Leads the Pack
OpenAI secured $6.6 billion at a post-money valuation of $157 billion, led by Thrive Capital. This funding round positions OpenAI, the creator of ChatGPT, among the most valuable private companies globally. Notable investors included Altimeter Capital, Fidelity, Khosla Ventures, Microsoft, Nvidia, SoftBank, and Abu Dhabi-based MGX. Reports indicated that SoftBank’s Vision Fund would contribute $500 million. This funding comes amid challenges for OpenAI, including a leadership exodus and a transition from a nonprofit to a for-profit benefit corporation, which also involves granting equity to co-founder Sam Altman. The funding structure, involving convertible notes, allows investors to reclaim their investments if the transition is not completed within two years, eliminating caps on returns. This round surpasses the previous largest funding of $6 billion raised by Elon Musk’s generative AI startup, xAI, earlier this year.
Pacific Fusion’s Ambitious Energy Goals
Pacific Fusion, focused on developing nuclear fusion energy, raised over $900 million in a Series A round led by General Catalyst. The funding is contingent on the company achieving specific milestones, which have not been disclosed. This investment underscores the growing interest in energy solutions capable of supporting AI’s substantial power requirements.
Crusoe Energy Systems Shifts Focus
Crusoe Energy Systems, originally aiding Bitcoin mining by utilizing natural gas, has pivoted to support AI infrastructure. The Denver-based company raised $500 million in a round led by Founders Fund, achieving a valuation of $3 billion. Founded in 2018, Crusoe has now raised a total of $1.2 billion.
Poolside’s Major Series B
Poolside, an AI software developer for programmers, closed a $500 million Series B round led by Bain Capital Ventures, bringing its valuation to $3 billion. The company has raised $626 million since its inception in May 2023.
X-energy’s Clean Energy Initiative
X-energy, based in Rockville, Maryland, raised approximately $500 million in a Series C-1 round, primarily backed by Amazon. The company is working on advanced small modular nuclear reactors aimed at clean energy generation, with plans to collaborate on over 5 gigawatts of new power projects by 2039.
Form Energy’s Renewable Innovations
Form Energy, specializing in multiday energy storage systems, secured $405 million in a Series F round led by T. Rowe Price. The company aims to enhance its manufacturing and deployment of iron-air battery systems, having raised a total of $1.5 billion since its founding in 2017.
Kailera Therapeutics Launches with Strong Backing
Kailera Therapeutics announced its launch with a $400 million Series A financing co-led by Atlas Venture, Bain Capital Life Sciences, and RTW Investments. The Boston-based company is developing therapies for chronic weight management.
Lightmatter’s Photonic Solutions
Lightmatter, which focuses on using light for AI-related calculations, raised $400 million in a Series D round led by T. Rowe Price, achieving a valuation of $4.4 billion. The company aims to address energy consumption and scalability challenges in AI data centers.
Splitero’s Innovative Home Equity Solutions
Splitero, a fintech startup, raised $300 million through a strategic investment from Antarctica Capital. The company provides homeowners with cash in exchange for a share of their home’s future value, having raised nearly $318 million since its founding in 2021.
Seaport Therapeutics Advances Biotech Solutions
Seaport Therapeutics, which focuses on treatments for neuropsychiatric disorders, secured $225 million in a Series B round led by General Atlantic. This follows a $100 million Series A raised earlier this year, as the company continues to develop its clinical-stage pipeline.
Global Funding Highlights
Outside the U.S., the largest deal was by GDS International, a China-based data center developer, which raised $1 billion from institutional private-equity investors.
Funding Methodology
This report tracks the largest funding rounds raised by U.S.-based companies in October 2024, based on data from a comprehensive database. While most rounds are included, there may be slight delays in reporting.
Frequently asked questions
Why was OpenAI's round structured with convertible notes?
The notes tie the investment to OpenAI completing its restructuring into a for-profit benefit corporation. If that does not happen within two years, investors can take their money back, and the structure removes caps on their returns.
What connects the energy deals to AI?
AI data centres consume very large amounts of power, so investors are funding supply as well as compute. X-energy's small modular reactors, Pacific Fusion's fusion work and Form Energy's iron-air storage all target that demand.
How high did a round need to be to make October's list?
Companies needed to raise more than $200 million to appear, a threshold the article attributes to unusually strong investor appetite for large deals that month.
