U.S. startups experienced an exceptional funding week between September 5 and 11, 2026, as four companies announced rounds worth at least $1 billion each. The Boring Co. topped the list with a $3 billion Series D, followed by Cognition, an artificial intelligence software company, with a $2 billion Series E.
The list is based on the largest announced rounds for U.S.-based companies according to the Crunchbase database, with the possibility of a limited delay in recording some rounds announced at the end of the week.
The Largest Rounds on the List
- The Boring Co.: The tunnel-boring company owned by Elon Musk and based in Bastrop, Texas, raised $3 billion led by the United Arab Emirates, with participation from Andreessen Horowitz, Sequoia Capital, and Valor Equity Partners. The round values the company at $23 billion, while its total funding reached approximately $3.9 billion. The company is developing tunnel networks to transport passengers and vehicles and already operates the Vegas Loop system beneath Las Vegas.
- Cognition: The San Francisco-based company secured $2 billion in a Series E led by Accel, Andreessen Horowitz, Avenir, Founders Fund, and General Catalyst. It is valued at $48 billion, while its total funding approached $3.9 billion. The company is known for its autonomous software-engineering assistant, Devin.
- Motive: The fleet-management platform raised $1.3 billion in private-equity funding led by General Catalyst. The platform, formerly known as KeepTruckin, uses artificial intelligence to manage fleets, monitor driver safety, and automate operations and spending.
- Stoke Space: The reusable-rocket development company closed a $1 billion Series E led by Point72 Ventures and Spark Capital, with participation from Y Combinator. The company reached a valuation of $10 billion, and its total funding rose to approximately $2.4 billion.
Funding Extends to Energy, Defense, and Infrastructure
Suniva, the U.S. manufacturer of high-efficiency solar cells, raised $835 million to expand domestic production, including a new facility in South Carolina that will increase its manufacturing capacity by more than four times. Mach Industries also secured $600 million in a Series C, raising its valuation to $3.7 billion. The company operates in unmanned aircraft, long-range weapons, and propulsion technologies.
In legal artificial intelligence, Harvey raised $550 million in a Series H, bringing its valuation to $15.5 billion. The company develops tools for legal research and the analysis of documents and contracts, while its total funding approached $1.8 billion.
Semiconductors and Artificial Intelligence Infrastructure
Fab2, formerly known as Atomic Semi, and Positron each raised $500 million. Fab2 develops tools, components, and software for designing smaller, faster, and less expensive semiconductor factories, while Positron manufactures hardware dedicated to artificial intelligence model inference and reached a valuation of $5 billion after the round.
Celero Communications also secured $275 million to develop coherent digital signal processor technology that transfers data between chips and data centers with greater energy efficiency. Encoded Therapeutics closed a $275 million round to develop precision genetic medicines, including a treatment targeting Dravet syndrome, a rare genetic form of epilepsy.
Why Does This Week Matter?
The rounds show that large-scale capital is not concentrated solely in artificial intelligence applications, but extends to the infrastructure required to operate them, such as semiconductors and networks, as well as strategic sectors including defense, space, and solar energy. At the same time, the size of the rounds alone does not establish the success of the products or their ability to generate returns; it reflects investor valuations and the availability of funding during that period, while the outcomes of expansion and execution remain open questions.