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Sequoia just led one of the boldest AI infrastructure bets yet — a $1 billion round for a company that builds nuclear reactors, not chips. Valar Atomics closed the Series B at a reported $6 billion valuation, with Sequoia partner Shaun Maguire joining the board as the startup races to power AI data centers the grid can’t keep up with.
If investors are now writing billion-dollar checks for nuclear power plants just to keep AI compute running, how much longer until energy access — not GPUs — becomes the industry’s real bottleneck? Elsewhere, a $1.28 billion acquisition and a security startup’s tripled valuation show just how much capital is still chasing AI-adjacent bets.
In today’s Startup News AI:
Valar Atomics raises $1B to build nuclear-powered AI data centers
Bending Spoons buys Airtable for $1.28B
Horizon3 triples its valuation to $2B on AI-security demand
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Valar Atomics closed a $1 billion Series B plus a $200 million credit facility, led by Sequoia Capital, to mass-produce small modular nuclear reactors built specifically to power AI data centers.
What’s the Deal?
Sequoia partner Shaun Maguire is joining Valar’s board, with Apandion Capital, Atreides Management, Conviction, Dream Ventures, HOF Capital, Point72, Riot Ventures, Snowpoint Ventures and Valor Equity Partners also participating.
The round reportedly values Valar at $6 billion, coming after the startup took its Ward 250 reactor critical in just seven months and used it to power an Nvidia Blackwell system.
Valar has already signed a development deal with Nvidia for a 30MW AI factory, positioning its factory-built reactors as a direct answer to the power constraints throttling AI data center buildouts.
Why care?
Nuclear power has jumped from a decade-out bet to a line item AI infrastructure investors will pay $1 billion for today. Founders building anything power-hungry — from model training to inference at scale — should expect energy supply to become as competitive a moat as chips.
Bending Spoons agreed to acquire Airtable in an all-cash deal worth $1.28 billion, picking up the spreadsheet-and-database startup that serves more than 500,000 organizations, including 80% of the Fortune 100.
What’s the Deal?
Airtable’s annual recurring revenue has reached roughly $480 million, up more than 20% year-over-year, even as its valuation has fallen sharply from an $11 billion peak in 2021.
The deal follows Airtable’s January 2026 launch of Superagent, an orchestration layer that lets customers deploy teams of AI agents to execute work inside the platform.
Bending Spoons — fresh off its own IPO and past acquisitions of WeTransfer and Vimeo — continues a buying spree of consumer and productivity software brands with built-in AI ambitions.
Why care?
A $1.28 billion exit for a company once valued at $11 billion shows how much AI-era product bets now weigh on what acquirers will pay, even for a company with growing revenue. Founders should note Bending Spoons keeps proving there’s a buyer for mature SaaS brands willing to sell below their peak.
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Horizon3 raised a $250 million Series E at a $2 billion valuation, tripling its price tag in just 14 months as enterprises rush to stress-test their systems against AI-driven attacks.
What’s the Deal?
New strategic investors EDBI, SAIC and Qualcomm joined returning backers NightDragon and NEA, betting on Horizon3’s NodeZero platform for continuous, automated penetration testing.
The company approached $100 million in annual recurring revenue last year on 120% year-over-year growth, running more than 310,000 production security tests without any live-system downtime.
Horizon3 is plowing $100 million into R&D and opening new offices in Amsterdam, Australia and Singapore to serve its roughly 7,200 customers.
Why care?
Security has become one of the clearest wedges for AI-native startups to sell into the enterprise, and Horizon3’s tripled valuation shows investors pricing in a long runway of AI-versus-AI conflict. Expect more security vendors to lean on “can you detect AI” as their core pitch to boards spooked by autonomous threats.
The Shortlist
Zenity raised a $125 million Series C led by Norwest, with SoftBank Vision Fund 2 and Intel Capital joining, to police autonomous AI agents across Microsoft Copilot, ChatGPT Enterprise and Gemini deployments.
HappyRobot landed a $150 million Series C at a $1.2 billion valuation, with Andreessen Horowitz and Y Combinator returning to back its AI agents that now handle millions of enterprise tasks a month for DHL and Uber.
Decade closed an $85 million seed round — the largest ever for a Latin American startup — backed by Greenoaks and Benchmark to pair Brazilian clients with AI-native wealth advisers.
Design Arena secured a $7.9 million seed round led by Index Ventures to scale its crowdsourced “taste” evaluation platform, which already counts 5.3 million users and $60 million in annual recurring revenue.