The Week’s 10 Biggest Funding Rounds: Large Rounds For AI Infrastructure, Space Tech And Investment Management Lead

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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 deal roundup here.

Following a stretch featuring multiple billion-dollar-plus investments, venture investors have dialed back the zeroes on their capital checks. Over the past week, the largest funding rounds for U.S. startups landed in the hundreds of millions. Leading the pack were a $550 million financing for AI infrastructure enterprise Temporal Technologies alongside a $308 million investment directed at space vehicle manufacturer Impulse Space.

The remainder of the top funding list highlighted primarily artificial intelligence-focused enterprises across fields such as investment management, coding, networking, and marketing, alongside selections in biotech and energy. Furthermore, data center builder Crusoe officially confirmed its previously reported raise exceeding $3 billion, which was co-led by Valor Equity Partners, Atreides Management, and Mubadala Capital.

1. Temporal Technologies, $550M, AI infrastructure: Temporal Technologies, which builds an open-source platform designed to create and manage long-running enterprise systems and AI agents, hauled in $550 million through a Series E funding round at a valuation of $12.55 billion. The financing for the Bellevue, Washington-based business was led by Lightspeed, Goldman Sachs Alternatives, Wellington Management, and Tiger Global.
2. Impulse Space, $308M, space tech: Based in Redondo Beach, California, Impulse Space builds space vehicles engineered to transport payloads across and between different orbits. The company secured a $308 million Series D extension, lifting the total combined value of the round to $808 million.
3. Ridgeline, $250M, investment management: Ridgeline, creator of an artificial intelligence-powered investment management platform, collected $250 million via a Series E round. Spearheaded by chairman and founder Dave Duffield, the financing established a $1.45 billion valuation for the Incline Village, Nevada-based firm.
4. Cornelis Networks, $205M, networking: Wayne, Pennsylvania-based Cornelis Networks develops specialized networking technology tailored for high-performance computing and AI workloads. The firm completed a $205 million capital injection supported by IAG Capital Partners.
5. Factory, $200M, AI software development: San Francisco-headquartered Factory delivers enterprise software development tools powered by artificial intelligence. The organization revealed a $200 million funding package carrying a $5 billion valuation, backed by a broad group of individual investors and venture firms.
6. Profound, $180M, AI marketing: Profound provides marketing software designed to help clients elevate their visibility within AI-generated responses. The New York startup closed a $180 million Series D round at a $1.8 billion valuation, led by Sequoia Capital and Kleiner Perkins.
7. (tied) Arcee AI, $150M, foundational AI: Arcee AI focuses on creating open-weight artificial intelligence models and finalized a $150 million Series B round valued at over $1 billion. Cambium Capital, Vista Equity Partners, and Emergence Capital spearheaded the round for this San Francisco-based enterprise.
8. (tied) Nex, $150M, gaming: Nex produces family-oriented digital games driven by body motion rather than traditional controllers. The San Francisco company gathered $150 million via new debt and equity financing, featuring a Series E led by BAI Capital and Baillie Gifford, though the firm did not specify the exact equity breakdown.
9. Mazama Energy, $135M, geothermal energy: Seattle-based geothermal energy developer Mazama Energy concentrates on superhot rock geothermal power. The organization secured $135 million in a Series B round steered by Centaurus Capital and Doerr Capital.
10. Sling Therapeutics, $123M, biotech: Ann Arbor, Michigan-based Sling Therapeutics develops small-molecule treatments for thyroid eye disease and closed a $123 million Series C round. Forbion Capital Partners headed the financing for the biotech company.

Methodology

We tracked the largest announced rounds in the Crunchbase database that were raised by U.S.-based companies for the period of Sept. 12-18, 2026. Although most announced rounds are in the database, there may be a small time lag, as some rounds are reported late in the week.

Illustration: Dom Guzman

?Frequently Asked Questions

01What was the largest startup funding round of the week?

Temporal Technologies led the week with a $550 million Series E funding round, bringing its valuation to $12.55 billion.

02Which sectors dominated the week’s top venture deals?

AI infrastructure, artificial intelligence software applications, space technology, and investment management captured the largest share of this week’s venture investments.

03What date range does this weekly funding report cover?

This report tracks announced funding rounds for U.S.-based companies from September 12 to September 18, 2026.