The 24 largest US startup funding rounds of June 2026

Key Takeaways

• MainFunc (Genspark) raised the largest total equity at $654.3M, signaling massive bets on AI-powered SME automation
• Infrastructure plays dominated: GPU cloud platforms, liquid cooling, and quantum computing attracted multiple nine-figure rounds
• Defense tech startup Twenty Technologies raised $138M just one year after founding, reflecting accelerated government tech cycles

June 2026 delivered some of the year's biggest venture bets, with 24 US startups pulling in rounds that tell a clear story: investors are doubling down on AI infrastructure, enterprise automation, and defense tech. The month's top rounds ranged from $100M to cumulative totals exceeding $650M, spanning everything from sales tax automation to quantum computing.

AlleyWatch compiled the data from Crunchbase, and the picture that emerges shows capital clustering around a handful of themes. GPU cloud providers, AI enterprise tools, and deep tech all attracted nine-figure checks. Here's what founders should know about where the smart money went.

Who raised the most in June 2026?

Palo Alto-based MainFunc tops the list with $654.3M in total equity funding. The company builds Genspark, an AI workspace targeting SME automation. Founded in 2023 by Eric Jing, Jamison Powell, Kaihua Zhu, Lenjoy Lin, and Wen Sang, MainFunc has grown aggressively. The sheer size of the raise suggests investors see a path to replacing significant portions of back-office labor for small and mid-sized businesses.

Cosm, the Los Angeles immersive media company, sits second at $350M total funding. Backed by Fox, Sony Pictures Entertainment, and Baillie Gifford, the company builds end-to-end experience technology for entertainment venues. Think dome theaters and next-generation sports viewing.

Cadence, a New York-based remote patient monitoring company, has now raised $241M. General Catalyst, Thrive Capital, and Coatue lead a syndicate betting that chronic disease management will shift permanently to home-based, tech-enabled care.

AI infrastructure attracted the deepest pockets

Three GPU and AI infrastructure companies landed on the list, reflecting the ongoing compute crunch. Runpod, a Mount Laurel cloud platform for GPU workloads, has raised $122M from Summit Partners, Intel Capital, and Dell Technologies Capital. The platform lets developers deploy full-stack AI applications without managing hardware.

Boulder-based Hydra Host raised $118.6M, backed by NVIDIA, Founders Fund, and NEA. The company operates what it calls "AI Factory Franchises," essentially standardized bare-metal GPU data centers run by independent operators but accessible through a unified platform.

ZutaCore, based in Foster City, pulled in funding that brought its total to $100M. The company develops liquid cooling systems for data centers and AI infrastructure. With GPU clusters generating increasingly dense heat loads, cooling has become a genuine bottleneck. Samsung Ventures and Mitsubishi Electric are among the backers.

Enterprise AI and compliance software

Numeral, a San Francisco sales tax automation platform, has now raised $157.5M. The company, founded in 2022 by Jake Moffatt, Matt DuVall, and Sam Ross, automates sales tax for e-commerce and SaaS businesses. The investor roster reads like a hall of fame: Y Combinator, Benchmark, Insight Partners, and Salesforce Ventures.

The Numeral raise reflects a real pain point. Since the 2018 Wayfair Supreme Court decision, online sellers face sales tax obligations in states where they have no physical presence. For a SaaS company selling to customers across all 50 states, the compliance burden is substantial. Manual processes don't scale.

Scaled Cognition, an Amesbury-based startup, raised $100M total. The company ensures that AI-powered customer interactions stay accurate and compliant with company policies. Khosla Ventures and Lerer Hippeau led. As enterprises deploy more AI chatbots and agents, the "hallucination problem" becomes a legal and brand risk. Scaled Cognition sits at that intersection.

Ent.AI, founded just last year in Santa Clara, already hit $100M in funding. The company offers end-to-end AI services: data labeling, model building, and strategy consulting. Sequoia Capital and Felicis backed the round. The speed of the raise suggests demand from enterprises that want AI but lack internal ML teams.

Defense and security tech accelerates

Twenty Technologies, based in Arlington, raised $138M just one year after its 2024 founding. The company builds cyber warfare software to automate offensive cyber operations. General Catalyst, Accel, and In-Q-Tel (the CIA's venture arm) backed the round. The speed from founding to nine-figure raise reflects how quickly defense procurement is moving for software-based capabilities.

Trase Systems, a McLean-based AI firm, raised $117.5M total. The company provides AI-powered safety and security tools for administrative workflows. ARCH Venture Partners and Red Cell Partners participated. McLean's proximity to the Pentagon and intelligence agencies isn't coincidental.

Deep tech and quantum computing

Atom Computing, based in Berkeley, has raised $190.2M to develop gate-based quantum computers using neutral atoms as qubits. Founded in 2018 by Benjamin Bloom and Jonathan King, the company competes against ion-trap and superconducting approaches. Venrock and Cisco Investments are among the backers. Quantum remains pre-commercial, but the funding signals belief that practical applications are within reach this decade.

GT Medical Technologies in Tempe raised $227.5M total for brain tumor treatment devices. Founded in 2017, the company has been at it long enough to move through clinical validation. Medical device timelines are measured in years, not months, and patient outcomes are the only metric that matters.

Sports and media bets

The Premier Lacrosse League, founded by brothers Michael and Paul Rabil in 2018, raised $100M from Ares Management, Arctos Sports Partners, and ESPN. The league has pushed lacrosse toward mainstream viability, and ESPN's participation suggests media rights have real value. Sports league equity has become an asset class of its own.

Taktile, a New York-based decision platform for financial institutions, rounds out the list. The company helps banks and lenders automate risk management with AI. Financial services remains one of the largest potential markets for applied AI, given the volume of decisions made daily on credit, fraud, and compliance.

What this means for founders raising now

If you're building in AI infrastructure, enterprise compliance, or defense, the capital is clearly available. But the bar is high. Most of these companies had either top-tier founder pedigrees, clear technical differentiation, or both. Numeral's backers include Y Combinator and Benchmark. Twenty Technologies landed In-Q-Tel. Ent.AI got Sequoia a year after founding.

The pattern isn't "AI is hot." It's more specific: investors want to fund AI companies that solve measurable business problems for customers who will pay enterprise prices. Workflow automation for SMEs, compliance for e-commerce, cooling for data centers. Each addresses a clear, growing pain.

Frequently Asked Questions

Which US startup raised the most funding in June 2026?

MainFunc, the maker of Genspark AI workspace, leads with $654.3M in total equity funding. The Palo Alto company targets SME automation and was founded in 2023.

What sectors attracted the most venture capital in June 2026?

AI infrastructure (GPU cloud platforms, liquid cooling), enterprise automation, defense tech, and healthcare technology dominated the largest rounds.

How much did Numeral raise for sales tax automation?

Numeral has raised $157.5M in total equity funding. The company automates sales tax compliance for e-commerce and SaaS businesses, backed by Y Combinator, Benchmark, and Salesforce Ventures.

Which defense tech startups raised funding in June 2026?

Twenty Technologies raised $138M for cyber warfare automation, backed by General Catalyst and In-Q-Tel. Trase Systems raised $117.5M for AI-powered security workflows.

Is quantum computing still attracting venture investment?

Yes. Atom Computing raised $190.2M total for its neutral-atom quantum computers. The Berkeley-based company competes with ion-trap and superconducting approaches.

Source: AlleyWatch