Musk's Boring Co. Tops Four-Billion-Dollar Week With $3B Series D

Elon Musk's tunnel-drilling company, The Boring Co., raised a $3 billion Series D, the largest U.S. startup round announced in the week covered by Crunchbase News' weekly funding roundup.

The round put the company at the top of a week that saw four companies each raise $1 billion or more. Behind The Boring Co. came Cognition, an AI coding startup, at $2 billion, and Motive, which landed $1.3 billion. Each of those deals was large enough to rank among the biggest single rounds of the week, and together they made it what the roundup described as a monster week for U.S. startup funding.

The Boring Co. is described in the source as Musk's tunnel-drilling company, placing the round squarely in the physical-infrastructure side of the venture market rather than the software and AI categories that dominated the rest of the top of the list.

The announcement did not name a lead investor for the Series D, and the source did not specify how the company intends to use the proceeds. No valuation was disclosed in the roundup either.

The rankings are drawn from Crunchbase's weekly feature tracking the top 10 announced funding rounds in the United States, published September 11, 2026 by Marlize van Romburgh. Deals of $100 million or more to U.S.-based companies also feed into the publication's Megadeals Board, which tracks large venture deals over the course of the year.

For The Boring Co., the $3 billion round is the headline entry in a week where capital concentrated at the very top of the market: three of the four billion-dollar raises went to companies in tunnels, AI coding and fleet technology, with the rest of the top 10 trailing well behind.