Mach Industries, which makes unmanned military vehicles and weapons, raised $600M in an extension to its $300M Series C, doubling its valuation to $3.7B (Julie Bort/TechCrunch)

Defense technology firm Mach Industries has significantly increased its valuation, doubling to $3.7 billion in just three months, following a $600 million Series C extension round. The original Series C round, announced in June, raised $300 million and valued the company at $1.8 billion. Notable investors in both rounds include Ribbit Capital, Infinite Capital, Bedrock Capital, and Sequoia.

Mach Industries specializes in the manufacturing of unmanned military vehicles and weapons, such as vertical takeoff and landing drones, long-range strike systems, and counter-drone systems. The company operates a 115,000-square-foot manufacturing facility in Huntington Beach, California, with additional locations across the state.

Mach aims to provide cost-effective, highly integrated systems that challenge incumbent defense contractors. In May, the company acquired Exquadrum, a solid rocket motor startup, for $50 million, capitalizing on the shortage of SRMs in the market dominated by two major players. Exquadrum's acquisition has led to the creation of Mach Energetics, a new business line focused on SRMs, jet engines, and energetic systems for other companies.

Founded by 22-year-old Ethan Thornton, Mach Industries exemplifies the growing interest from classic Silicon Valley venture capitalists in defense tech startups. Thornton, who dropped out of MIT at age 19, secured Sequoia's Stephanie Zhan and Shaun Maguire as investors early in the company's development. Following a U.S. Army contract, Mach Industries has also attracted attention from Ribbit Capital, which has recently invested in high-profile AI deals.