This is a monthly feature that runs down the month’s top 10 funding rounds in the U.S. Check out February’s biggest rounds here.
March was a pretty good month for big rounds. To even make the list, a company needed to raise $200 million. Not surprisingly, a big artificial intelligence raise led the way.
1. Anthropic, $3.5B, artificial intelligence: Anthropic, a ChatGPT rival with its AI assistant Claude, raised a $3.5 billion funding round led by Lightspeed Venture Partners, valuing it at $61.5 billion. The San Francisco-based startup was most recently valued at $18.5 billion in February 2024. The new round briefly made Anthropic the second-most valuable AI startup in the world. However, late last month, xAI bought X, with the deal valuing the startup at now $80 billion. Anthropic’s new round also values it well behind OpenAI, which is closing in on its own new $40 billion funding from SoftBank that will value it at a mind-blowing $260 billion.
2. Nerdio, $500M, information technology: IT professionals are stretched pretty thin these days, so it makes sense that a company that helps automate some of their work could raise big. That’s exactly what Nerdio did. The Chicago-based company raised a $500 million equity round from General Atlantic that values it at $1.2 billion, according to Bloomberg. While the company may be under the radar for some, it says it has more than 15,000 customers in 50 countries, is profitable and growing annual recurring revenue more than 85% year to year. Founded in 1998, Nerdio has raised $625 million, per Crunchbase.
3. Fleetio, $450M, fleet management: Fleet optimization software platform developer Fleetio locked up a $450 million round to finance the acquisition of maintenance authorization platform Auto Integrate. The new round was co-led by existing Fleetio investor Elephant and new investor Goldman Sachs Alternatives’ growth equity branch, and values the Birmingham, Alabama-based company at more than $1.5 billion. The new company will service more than 8 million vehicles and process more than 13 million repair orders per year. Founded in 2011, the company has raised $620 million, per Crunchbase.
4. Mercury, $300M, fintech: Fintech startup Mercury raised a massive $300 million Series C led by new investor Sequoia Capital. The new round includes primary and secondary funding and values the company at $3.5 billion — more than double its previous Series B valuation of $1.6 billion in 2021. The San Francisco-based company offers bank accounts integrated with various financial tools businesses need. Founded in 2017, the company has raised $452 million, per Crunchbase.
5. Flock Safety, $275M, public safety: Atlanta-based Flock Safety raised a $275 million round led by Andreessen Horowitz that values the startup at $7.5 billion. The company’s integrated safety platform includes license plate readers, gunshot detection, AI-powered video cameras and drone-as-first-responder technology. The company also has surpassed $300 million in annual recurring revenue. Founded in 2017, the company has raised nearly $656 million, per Crunchbase.
6. (tied) Celestial AI, $250M, semiconductor: Optical interconnectivity startup Celestial AI raised a $250 million Series C1 round led by Fidelity Management & Research Co. at a reported $2.5 billion valuation. The fresh cash comes almost exactly a year after the Santa Clara, California-based company locked up a $175 million Series C led by Thomas Tull’s US Innovative Technology Fund. The startup’s photonic fabric platform helps separate compute and memory, making processing extensive AI faster and providing more energy-efficient computing. Founded in 2020, Celestial AI has now raised more than $515 million, per the company.
6. (tied) Epirus, $250M, defense: Startup Epirus raised a $250 million Series D led by 8VC 1 and Washington Harbour Partners in the latest example of a defense tech raising big. The Los Angeles-based company has developed a high-energy, high-power microwave technology to counter drones, drone swarms and other electronics. The new round included a strategic investment from General Dynamics Land Systems. Epirus — founded in 2018 — did not release a valuation after the new round but has raised more than $550 million, per the company, and plans to use the new funds to expand into international and commercial markets, and grow its workforce.
6. (tied) Island, $250M, cybersecurity: Dallas-based enterprise browser developer Island raised a $250 million Series E at a $4.8 billion valuation. The new round was led by Coatue Management, with several existing investors participating in the round, per the company. The new valuation represents a 60% jump from last April when Island raised a $175 million Series D at a $3 billion valuation, also led by Coatue. The company has approximately 500 employees, with more than 200 in product development and engineering, and more than 450 customers. The deal came just after Google parent Alphabet announced its intention to buy cloud security unicorn Wiz for $32 billion — the biggest ever M&A exit for a VC-backed company. That deal likely will stoke investor interest in cyber, which already saw venture funding increase last year compared to 2023. Island itself is no stranger to big-money rounds. In October 2023, it raised a $100 million Series C led by Prysm Capital that valued the company at $1.5 billion. In March 2022, it announced a $115 million Series B at a $1.3 billion valuation led by Insight Partners — minting it a unicorn just seven weeks after launching. Founded in 2020, the company has raised $810 million, per Crunchbase.
9. Shield AI, $240M, defense: The direct hits just keep coming for the defense tech sector as defense and aerospace startup Shield AI locked up a $240 million F-1 strategic funding round at a $5.3 billion valuation. The new valuation is nearly double the company’s previous $2.7 billion valuation after it raised a $200 million Series F in October 2023 (it later added another $300 million in debt and equity to the round). San Diego-based Shield AI creates an array of intelligent, autonomous systems for the defense sector. Its software, for instance — Hivemind Mind — enables aircraft to operate autonomously in high-threat environments. The new funding received what the company called “major participation from strategic investors” Hanwha Aerospace and L3 Harris Technologies, as well as participation from existing investors including Andreessen Horowitz, US Innovative Technology Fund and Washington Harbour Partners. Founded in 2015, Shield AI has raised $1.3 billion, per Crunchbase.
10. Lila Sciences, $200M, life science: The intersection of artificial intelligence and science is seeing a lot of money, and here’s another example. Cambridge, Massachusetts-based Lila Sciences raised a huge $200 million seed round from the likes of Flagship Pioneering and others. The new company is looking to build the world’s first scientific superintelligence platform and fully autonomous labs for life, chemical and materials sciences by using an advanced form of AI that can not only process vast amounts of data and make predictions, but also assist scientists in “designing and conducting new experiments, generating hypotheses and testing them in real-world environments.”
Big global deals
The biggest funding round outside the U.S. was a crypto deal.
Methodology
We tracked the largest rounds in the Crunchbase database that were raised by U.S.-based companies for the month of March 2025. Although most announced rounds are represented in the database, there could be a small time lag as some rounds are reported late in the month.
Illustration: Dom Guzman
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