AI infrastructure led the largest announced funding rounds for U.S. startups between August 29 and September 4, 2026, with Crusoe raising $3 billion in a Series F round, while Fluidstack secured $1.5 billion in a round from private equity investors. The two rounds offer a clear indication that capital continues to be directed toward data centers, cloud services and the computing capacity required to run large-scale AI workloads.
The Two Largest Rounds
Atreides Management and Valor Equity Partners led Crusoe’s round, with participation from Mubadala Capital. The company began by using stranded natural gas to power cryptocurrency mining, but later shifted to becoming a cloud and data center provider for AI, serving customers including OpenAI, Microsoft and Meta. According to Crunchbase, Crusoe has raised approximately $7.2 billion to date, and its post-round valuation reached $30 billion, three times its valuation less than a year earlier.
New York-based Fluidstack raised $1.5 billion in a round led by Jane Street Capital, bringing its total funding to slightly more than $2.6 billion and its valuation to $18 billion. The company provides extensive infrastructure for graphics processing units and data centers dedicated to AI workloads.
Other Rounds on the List
- Gimlet Labs: Raised $300 million in a Series B led by Andreessen Horowitz, reaching a valuation of $3 billion. The company is developing an AI inference cloud that distributes workloads across different types of chips.
- Upwind Security: Received $300 million, reaching a valuation of $3.8 billion. Its platform uses real-time cloud runtime data to detect threats and vulnerabilities.
- David: The high-protein food company raised $250 million at a valuation of $2.25 billion.
- HiBob: Raised $166 million for its Bob platform for human resources, payroll, benefits and employee management, reaching a valuation of $3.2 billion.
- Lyte AI: Raised $165 million in a Series C, reaching a valuation of $1.6 billion. The company develops custom chips, sensors and software that help robots perceive their surroundings.
- TabaPay: Received $155 million to fund money-transfer and payments infrastructure, as it seeks to acquire Transact Bank.
- Thyme Care: Raised $125 million in a Series E for cancer-care coordination and oncology-care management services, reaching a valuation of $2 billion.
- HiddenLayer: Raised $100 million in a Series B to develop tools that protect AI models, agents and workflows from attacks and vulnerabilities.
Why Does This Trend Matter?
The list shows that spending is not focused solely on building AI models, but extends to the layers that make their use possible: data centers, graphics processing units, inference, security and systems that connect software to the physical world. The presence of companies such as Upwind Security and HiddenLayer also reflects growing demand to protect cloud infrastructure and AI systems as they move into production environments.
However, funding rounds alone do not prove these companies’ success or their ability to generate sustainable returns. The list also measures announced rounds for companies based in the United States, and some deals may take time to appear in the Crunchbase database, so it does not necessarily represent all startup funding activity globally. The figures indicate the size of the investment bet, not the actual operating results.