Temporal Technologies tops week with $550 million round

This week's list marks a shift from the recent pattern of multiple billion-dollar-plus rounds. The largest U.S. startup financings tracked by Crunchbase for Sept. 12-18, 2026 were in the hundreds of millions, with AI infrastructure company Temporal Technologies leading at $550 million. The deal valued the Bellevue, Washington-based developer of an open source platform for long-running AI agents at $12.55 billion, with Lightspeed, Wellington Management, Goldman Sachs Alternatives, and Tiger Global leading.

Beyond the top slot, the list was heavily weighted toward AI-focused companies across investment management, networking, coding and marketing, alongside energy and biotech. Data center developer Crusoe made official a previously reported $3 billion-plus raise co-led by Atreides Management, Valor Equity Partners and Mubadala Capital — a reminder that larger deals can still surface outside the weekly ranking. Round sizes ranged from Temporal's $550 million down to Sling Therapeutics' $123 million for a small-molecule thyroid eye disease therapy.

The week's smaller headline numbers may reflect deal timing as much as a change in investor appetite, since some rounds are reported late in the week and may not yet appear in the database. For startups preparing to raise and for the investors backing them, the more telling signal may be whether next week's list returns to billion-dollar territory or continues at this scale.