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The week's 10 biggest funding rounds: space tech, AI infrastructure lead fundraises. March 6, 2026 Want to keep track of the largest startup funding deals in 2025 with our curated list of $100 million-plus venture deals to U.S.-based companies? Check out The Crunchbase Megadeals Board. This is a weekly feature that runs down the week's top 10 announced funding rounds in the U.S. Check out last week's biggest funding deal roundup here. The first week of March was a relatively brisk period for large startup funding rounds, led by three deals of $500 million or more in the space tech and AI infrastructure sectors. In addition, we saw some good-sized deals around healthcare, neuroscience and enterprise software. 1. Sierra Space, $550M, space tech: Sierra Space, a space and defense tech company that designs and manufactures satellites, spacecraft and space subsystems, secured $550 million in equity funding led by LuminArx Capital Management. The financing sets an $8 billion valuation for the 5-year-old, Louisville, Colorado-based company. 2. (tied) Ayar Labs, $500M, AI infrastructure: Ayar Labs, a producer of co-packaged optics for use in AI infrastructure, landed $500 million in Series E funding led by Neuberger Berman. The financing sets a $3.75 billion valuation for the 11-year-old, San Jose, California-based company. 2. (tied) Vast, $500M, space tech: Long Beach, California-based Vast, a startup developing next-generation space stations, announced it has raised $500 million in fresh funding. The financing includes $300 million in Series A equity and $200 million in debt, with Balerion Space Ventures as lead investor. 4. Findhelp, $250M, care platform: Findhelp, developer of a platform to coordinate care across health systems, governments, benefits providers and other entities, secured $250 million in investment from TPG's The Rise Fund. Founded in 2010, Austin-based Findhelp describes its mission as connecting people to help and support systems. 5. Science Corp., $230M, neurotech: Alameda, California-based Science Corp., a biotech startup focused on brain-computer interface technologies, announced it has closed on a $230 million Series C fundraise. Lightspeed Venture Partners, Khosla Ventures, Y Combinator, IQT and Quiet Capital were among the investors participating in the syndicated round. 6. Cart.com, $180M, e-commerce: Cart.com, provider of an e-commerce platform and logistics services for brands to sell across digital channels, picked up $180 million in growth equity investment. Springcoast Partners led the financing for the Houston-based company. 7. Grow Therapy, $150M, mental health care: Grow Therapy, a New York-based platform for providing mental health care, raised $150 million in Series D funding led by TCV and Goldman Sachs Growth Equity. 8. Cognito Therapeutics, $105M, neuroscience: Cambridge, Massachusetts-based Cognito Therapeutics, a developer of therapies for neurodegenerative diseases, secured $105 million in Series C funding. Morningside, IAG Capital Partners and Starbloom Capital led the financing. 9. Nominal, $80M, engineering software: Nominal, a self-described provider of tools for engineers to test and operate critical technology, picked up $80 million in new funding. Founders Fund led the financing, which set a $1 billion valuation for the Austin-based company. 10. Sage, $65M, health software: New York-based Sage, provider of a software platform for senior living and skilled nursing, raised $65 million in Series C funding led by Goldman Sachs Alternatives. Methodology. We tracked the largest announced rounds in the Crunchbase database that were raised by U.S.-based companies for the period of Feb. 28-March 6. Although most announced rounds are represented in the database, there could be a small time lag as some rounds are reported late in the week. Stay up to date with recent funding rounds, acquisitions, and more with the Crunchbase Daily. March 5, 2026 Science Corp., a biotech startup focused on brain-computer interface technologies, announced Thursday that it has closed on a $230 million Series C... March 5, 2026 San Francisco-based Denki, which has built AI-powered software for financial auditors at public companies, has raised $4.1 million in funding, the... March 5, 2026 February closed with the largest startup investment of all time - OpenAI's $110 billion financing - but did not bring a jump in overall deal count... March 4, 2026 Over 127,000 workers at U.S.-based tech companies were laid off in mass job cuts in 2025, per a Crunchbase News tally, and the layoffs have continued... April 3, 2025 Discover and act on private market opportunities with predictive company intelligence.

Sierra Space valued at $8 billion as investors double down on defense, space tech. March 5 (Reuters) - Sierra Space said on Thursday it has raised $550 million in a Series C funding round that values it at $8 billion, as investor appetite for national security assets grows amid geopolitical tensions and strong interest in commercial space infrastructure. Space companies with government contracts and proven production capacity are seeing more capital flow, amid a broader push toward space-based data centers and orbital infrastructure. Investors are also closely watching SpaceX's expected initial public offering, which could reshape the competitive landscape in the sector. Sierra Space said the funding round was led by LuminArx Capital Management, with participation from existing backers including General Atlantic, Coatue, Moore Strategic Ventures and Andalusian Private Capital. The Louisville, Colorado-based company has sought to position itself as a key supplier of satellites, space transportation systems and defense technologies to U.S. national security customers. It had raised $290 million in a Series B round in 2023 which valued the company at $5.3 billion. The space company said the fresh capital would support expanded production capacity and development of solutions for defense and intelligence missions. "As we scale, our priority remains strengthening national security capabilities while delivering the discipline, reliability, and performance our government and commercial partners depend on," CEO Dan Jablonsky exclusively told Reuters. Space-based assets are playing an increasingly central role in intelligence gathering, secure communications and other critical defense missions as governments seek greater resilience and real-time data. Sierra Space has won cornerstone contracts including a $450 million award to build more than four satellites for a national security customer and a Space Development Agency contract with a potential value of up to $740 million. Beyond satellites, the company is developing the reusable Dream Chaser spaceplane, designed to ferry cargo, and eventually crew, to low Earth orbit. It completed key manufacturing milestones in 2025, with a demonstration flight planned for late 2026. (Reporting by Akash Sriram in Bengaluru; Editing by Krishna Chandra Eluri)

Sierra Space has raised $550 million in a Series C funding round led by LuminArx Capital Management, valuing the spacecraft manufacturer at approximately $8 billion. Existing investors also participated in the round. Based in Louisville, Colorado, Sierra Space was formed in 2021 as a commercial spinout of Sierra Nevada Corporation. The company initially focused on its Dream Chaser reusable spaceplane for ISS cargo missions, with a demonstration flight planned for late 2026. Sierra Space has recently expanded into defence markets, securing contracts to build missile-tracking satellites for the Space Development Agency. The funding will support the company's national security space efforts and manufacturing expansion in Colorado. The round follows the recent appointment of Dan Jablonsky as chief executive officer.