The 10 Biggest Rounds Of April: Safe Superintelligence’s $2B Round Leads The Way

This is a monthly feature that runs down the month’s top 10 funding rounds in the U.S. Check out March’s biggest rounds here.

Not surprisingly, artificial intelligence led the way for big funding rounds last month, but that wasn’t the only tech that interested investors. Startups in fintech, energy and more all landed big rounds as investors showered some cash in April.

1. Safe Superintelligence, $2B, artificial intelligence: AI research lab Safe Superintelligence snatched its second large raise in fewer than seven months. SSI, co-founded by OpenAI‘s former chief scientist Ilya Sutskever, reportedly raised a $2 billion round at a $32 billion valuation led by Greenoaks Capital Partners. The startup, which is looking to develop safe artificial intelligence systems, raised a $1 billion round from a litany of big-name investors including Andreessen Horowitz and Sequoia Capital last September.

2. Plaid, $575M, fintech: Plaid raised a $575 million round led by Franklin Templeton at a $6.1 billion valuation. The San Francisco-based company plans to use the cash to pay employee tax withholding obligations related to share conversion and to offer some liquidity to employees via a tender offer. Plaid, which connects user bank accounts to fintech apps, had a planned $5.3 billion sale to Visa scrapped back in 2021 following regulatory issues.

3. Silicon Ranch, $500M, energy: Nashville, Tennessee-based Silicon Ranch raised $500 million from European infrastructure investor AIP Management. The big investment is likely a bet on the U.S.’ increasing electricity demands. Back in 2022, Silicon Ranch — which operates solar and battery projects — raised $775 million in equity capital led by Manulife Investment Management. Founded in 2011, the energy company has raised more than $2 billion, according to Crunchbase data.

4. Chainguard, $356M, cybersecurity: Software supply chain security startup Chainguard raised a massive $356 million Series D at a valuation of $3.5 billion as companies look for ways to secure software development. The new funding was co-led by new investor Kleiner Perkins and existing investor IVP. The new valuation is a more than threefold increase from the $1.12 billion valuation the company received after a $140 million Series C led by IVP, Lightspeed Venture Partners and Redpoint. Chainguard allows companies to securely build software, providing guarded open-source software and eliminating threats in the software supply chains. The Kirkland, Washington-based company has grown its annual recurring revenue to $40 million and plans to reach more than $100 million in ARR before the end of fiscal year 2026. Founded in 2021, Chainguard has raised $612 million, per the company.

5. Runway, $308M, artificial intelligence: New York-based Runway raised $308 million in a new round at about double its valuation from less than two years ago. The new round — led by General Atlantic — values the AI video startup at more than $3 billion, per reports. In June 2023, the company raised a $141 million extension to its December 2022 $50 million Series C. Runway makes software that lets users create videos using text prompts or images. Runway also recently unveiled its new AI model, Gen-4, that allows users to create videos with consistent characters and backgrounds. Last fall, the company signed a deal with production company LionsGate to create a customized video-generation model. The startup plans to use the fresh cash to develop AI focusing on its film and animation studio. Founded in 2018, it has raised more than $540 million, per Crunchbase.

6. True Anomaly, $260M, space: Centennial, Colorado-based True Anomaly, which develops hardware and software systems to help space security and readiness, is used to large raises. Back in late 2023, the space tech startup raised a $100 million round led by Riot Ventures. It’s back again after raising a $260 million Series C led by Accel. The startup helps the government and commercial customers keep an eye on threats to assets they have in space, such as satellites. Founded in 2022, the company has raised $418 million, per Crunchbase.

7. Mainspring Energy, $258M, energy: Mainspring Energy secured a $258 million Series F led by General Catalyst. The Menlo Park, California-based firm builds generators — a business that has become appealing to investors as artificial intelligence continues to suck down energy. The company already is shipping generators — which can provide 10s of megawatts of power — to U.S. data center customers this year. Founded in 2010, the company has raised $813 million, per Crunchbase.

8 (tied). Apex, $200M, space: Less than a year after landing a $95 million Series B, space manufacturing company Apex locked up a $200 million Series C led by 8VC1 and Point72 Ventures. The Los Angeles-based startup is helping streamline the approach to satellites with the ability to mass produce spacecraft buses — the main body and structural component of satellites — to help meet increasing demand from customers like the U.S. Department of Defense. Founded in 2022, the company has raised $322 million, per Crunchbase.

8 (tied). Base Power, $200M, energy: Battery startup Base Power raised a $200 million Series B as the startup looks to expand nationally. The round was led by Addition. The Austin, Texas-based startup installs residential backup power systems — designed to charge batteries specifically when electric prices are low. Founded in 2023, the company has raised $268 million, per Crunchbase.

8 (tied). Persona, $200M, cybersecurity: Cybersecurity has proven pretty strong with investors recently, and last month was no exception. Verified identity platform Persona raised a $200 million Series D co-led by Founders Fund and Ribbit Capital that values the company at $2 billion. The San Francisco-based startup’s identity platform allows businesses to securely collect, verify, manage and make decisions about individuals’ and businesses’ identities. Founded in 2018, the company has raised nearly $418 million, per Crunchbase.

8 (tied). Supabase, $200M, database: Database developer Supabase raised a $200 million Series D led by Accel at a $2 billion valuation. The San Francisco-based startup is the developer of an open-source relational database — also called Supabase — for AI app development and competes with Google’s database Firebase. Founded in 2020, the company has raised $396 million, per Crunchbase.

Big global deals

The biggest funding round outside the U.S. came from Japan:

• Dennou Kotsu, a developer of a taxi dispatch system, raised a Series D worth approximately $343 million.

Methodology

We tracked the largest rounds in the Crunchbase database that were raised by U.S.-based companies for the month of April 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.