The Boring Company is angling to more than triple its valuation with a $4 billion capital infusion that would value Elon Musk’s tunneling business at $20 billion, according to people familiar with the matter. The existing Vegas Loop beneath the Las Vegas Convention Center already moves passengers in Teslas through underground tunnels, and the company has opened talks on major expansions under Nashville and Dubai while pitching additional projects in Baltimore, Chicago, and Los Angeles. Regulatory hurdles have mounted alongside the ambitions: Nevada regulators flagged nearly 800 environmental violations at construction sites last year and multiple workers have been seriously injured during tunneling operations. The potential raise extends a remarkable year across Musk’s portfolio, with SpaceX completing the largest public offering on record in June and xAI closing a $20 billion round in January.