The Week’s 10 Biggest Funding Rounds: AI, Space, and Fintech Take Center Stage

Every week we pull together the biggest venture checks that have hit the headlines, and this past round was a bit of a reality check. After a string of billion‑dollar financings earlier in the year, the top U.S. deals this week landed comfortably in the hundreds‑of‑millions range – still impressive, just a touch more down‑to‑earth.

Leading the pack was Temporal Technologies, the open‑source AI‑agent platform out of Bellevue, Washington. The company closed a $550 million Series E, catapulting its valuation to $12.55 billion. Lightspeed, Wellington Management, Goldman Sachs Alternatives and Tiger Global all wrote checks, signaling that the AI infrastructure market is still the darling of investors.

Hot on Temporal’s heels was Impulse Space, a Redondo Beach, California‑based venture building spacecraft that shuttle payloads between orbits. An extension of its Series D brought in $308 million, pushing the total raised to $808 million – enough to keep its rockets humming for years.

In the world of finance, Ridgeline, an AI‑enabled investment‑management platform nestled in Incline Village, Nevada, grabbed $250 million in a Series E round led by founder‑chairman Dave Duffield. The fresh capital set a fresh $1.45 billion valuation, underscoring how AI is reshaping how money is managed.

Networking for AI and high‑performance computing got its moment with Cornelis Networks. The Pennsylvania‑based firm secured $205 million from IAG Capital Partners, aiming to accelerate data‑center connectivity for the next generation of workloads.

San Francisco’s Factory, a maker of AI tools for enterprise software development, announced a $200 million raise at a $5 billion valuation. The round brought together a who's‑who of venture firms and a handful of individual angels – a sign that developers still crave smarter code assistants.

Marketing also got a boost: Profound, a New York startup that helps brands stand out in AI‑driven search results, raised $180 million in a Series D round led by Sequoia Capital and Kleiner Perkins, valuing the company at $1.8 billion.

Two companies tied for the seventh spot. First, Arcee AI from San Francisco, a developer of open‑weight AI models, took in $150 million in Series B funding, crossing the $1 billion valuation mark. Meanwhile, Nex, a family‑focused gaming studio that trades controllers for body motion, also netted $150 million in a mix of equity and debt, with Baillie Gifford and BAI Capital leading the charge.

The clean‑energy corner wasn’t left out. Seattle‑based Mazama Energy, which is pioneering super‑hot‑rock geothermal power, raised $135 million in a Series B round led by Centaurus Capital and Doerr Capital.

Finally, in biotech, Ann Arbor’s Sling Therapeutics secured $123 million in a Series C round to push its small‑molecule therapy for thyroid‑eye disease forward, with Forbion Capital Partners at the helm.

Our methodology is simple: we scan Crunchbase for U.S. companies that announced funding between Sept. 12‑18 2026 and filter for deals over $100 million. The list may lag a few days because some rounds are reported later in the week, but it gives a solid snapshot of where capital is flowing right now.