Want to keep track of the largest startup funding deals in 2024 with our curated list of $100 million-plus venture deals to U.S.-based companies? Check out The Crunchbase Megadeals Board.

This is a weekly feature that runs down the week’s top 10 announced funding rounds in the U.S. Check out last week’s biggest funding rounds here.

It is no shock to see the company that tops this list — a $6.6 billion raise makes a lot of headlines. However, it was far from the only big round this week, as seven of them topped $100 million — including $500 million for yet another AI company.

1. OpenAI, $6.6B, artificial intelligence: OpenAI announced its long-awaited raise of $6.6 billion at a post-money valuation of $157 billion led by Thrive Capital. The new round makes the ChatGPT creator one of the most valuable private companies in the world and also included investment from the likes of Altimeter Capital, Fidelity, Khosla Ventures, Microsoft, Nvidia, SoftBank and Abu Dhabi-based MGX. Just this week it was reported SoftBank’s Vision Fund would invest $500 million in the round. The new round comes just as the company is facing myriad issues, including an exodus of higher-up employees and a restructuring change to switch it from a nonprofit to a for-profit benefit corporation and to give co-founder Sam Altman equity in the company. The funding structure seems to take those factors into account, as it came in the form of convertible notes and reportedly allows for investors to ask for their money back if the change is not completed within two years and removes the cap on returns for investors. The new round is bigger than the $6 billion round Elon Musk’s generative AI startup, xAI, officially announced in May — which was the largest round raised this year.

2. Poolside, $500M, artificial intelligence: Most weeks a half-billion-dollar round would top this list — but this isn’t most weeks. Poolside closed a $500 million Series B led by Bain Capital Ventures. The new round values the startup at $3 billion, Bloomberg reported. The startup builds artificial intelligence software for programmers. Poolside is just one of a handful of big deals recently in the AI coding space. In August, San Francisco-based Magic, which also develops AI models to write software, raised a $320 million round, and AI-powered coding assistant Codeium closed a $150 million Series C. Poolside has raised $626 million since being founded in May 2023.

3. Kailera Therapeutics, $400M, biotech: Biotech was even bigger this week than normal. Case in point — Kailera Therapeutics’ massive raise. The Boston-based biotech announced its launch this week with a $400 million Series A financing co-led by Atlas Venture, Bain Capital Life Sciences and RTW Investments. The new company is developing several clinical-stage injectable and oral therapies to help with chronic weight management.

4. Aktis Oncology, $175M, biotech: Boston-based Aktis Oncology, a clinical-stage biotech startup developing novel targeted alpha radiopharmaceuticals to treat a broad range of solid tumors, closed a $175 million Series B led by Janus Henderson Investors, RA Capital Management and RTW Investments. In 2022, the company closed an $84 million extension round partially funded by large pharma companies such as Merck, Bristol Myers Squibb and Novartis, after raising a $72 million Series A round in 2021. Founded in 2021, the company has raised $331 million, per Crunchbase.

5. Impulse Space, $150M, space: Space tech seems to be having a moment again right now. Impulse locked up a $150 million Series B led by Founders Fund. The Redondo Beach, California-based space startup is developing a line of orbital transfer vehicles — also called “space tugs” — which serve as a last-mile cargo delivery service once payloads get into orbit. Founded in 2021, the company has raised $225 million, per Crunchbase.

6. (tied) Nusano, $115M, healthcare: Valencia, California-based Nusano, a physics startup developing radioisotopes for medical and industrial uses, announced a $115 million-plus Series C led by the Wasatch Group. Founded in 2013, this is the company’s first round of a disclosed amount, per Crunchbase.

6. (tied) Triveni Bio, $115M, biotech: Triveni Bio, a Watertown, Massachusetts-based biotech startup developing antibody treatments for immunological and inflammatory disorders, locked up a $115 million Series B led by Goldman Sachs Alternatives. Founded in 2019, the company has raised $207 million, per Crunchbase.

8. Eon, $77M, cloud management: New York-based Eon, a cloud backup startup, launched from stealth and announced a $77 million Series B led by Greenoaks. The company also announced it has raised a total of $127 million in funding.

9. Crescendo, $50M, artificial intelligence: Crescendo, a developer of an  augmented-AI customer experience platform, closed a series of venture round financings totaling $50 million. The last was led by General Catalyst and valued the San Francisco-based company at $500 million post this investment.

10. (tied) DataPelago, $47M, data: Mountain View, California-based DataPelago, which offers data analytic tools, launched from stealth with $47 million in funding from several investors.

10. (tied) Nym, $47M, productivity: Nym, a New York-based autonomous medical coding startup, raised a $47 million growth investment led by PSG Equity. Founded in 2018, the company has raised nearly $95 million, per Crunchbase.

Big global deals

The biggest deal of the week outside the U.S. came from across the pond.

• London-based Newcleo, an atomic energy company focused on developing advanced nuclear energy technologies, raised nearly $148 million in a Series A.

Methodology

We tracked the largest announced rounds in the Crunchbase database that were raised by U.S.-based companies for the seven-day period of Sept. 28 to Oct. 4. Although most announced rounds are represented in the database, there could be a small time lag as some rounds are reported late in the week.

Illustration: Dom Guzman