Mach Industries, the autonomous defence systems company founded by 22-year-old Ethan Thornton, has raised $600 million in a Series C extension at a valuation of $3.7 billion.
The latest funding round comes just three months after Mach secured $300 million at a valuation of $1.8 billion. The earlier round was led by Ribbit Capital, Infinite Capital, Bedrock Capital and Sequoia Capital.
Thornton launched the company in 2023, aged 19, and has since expanded it into a business developing six weapons programmes. Mach now operates from a 115,000-square-foot headquarters and manufacturing facility in Huntington Beach, California.
The company plans to develop airframes and jet engines alongside solid rocket motors, energetic systems and autonomous technologies. It is now moving from several years of development and testing towards production.
Mach Industries targets defence production
Thornton said private investment allowed Mach to take risks before a major military programme was in place, while building its manufacturing capability alongside its products.
“For a company like Mach, private capital lets us take risk earlier. We can build before there’s a massive program behind something, test it, learn from it and change it quickly,” he said.
“And because we think about manufacturing from the beginning, we’re not designing something and figuring out how to produce it years later. We’re building the product and the production capability at the same time.”
Mach secured a deal with the Army Applications Laboratory in 2024 to develop a vertical-takeoff precision cruise missile. Its growth comes as investment in defence technology accelerates, with $19.8 billion deployed into the sector in the first quarter of 2026, according to the source material.
Thornton’s interest in military technology began during his childhood in a military family in Texas. By the age of 16, he was prototyping defence applications on his parents’ property, including hydrogen-powered weapons using materials bought from Home Depot and Amazon.
He later studied aerospace at MIT and worked with Lincoln Laboratory, the university’s federally funded defence research centre. Before completing his first year, he received a Thiel Fellowship and left the university to work on Mach full-time.
Sequoia Capital led a $5.7 million funding round for Mach in June 2023, its first investment in a hardware defence technology company. Stephanie Zhan, the Sequoia partner who led the investment, described Thornton as having “technical depth and genuine obsession with the problem” as well as a “bias for action”.
Thornton has said that building a company at a young age has reinforced the importance of hiring people with expertise he does not have.
“Find people who are better than you at the things you don’t know, who will challenge you and who believe in what you’re trying to build,” he said.
He also advised other young founders to accept mistakes while maintaining confidence in the problem they are trying to solve. “You have to be willing to learn as you go, make mistakes and keep moving,” Thornton said.
