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US AI Startups Continue to Attract Mega-Rounds in 2025: A Deep Dive into the Funding Landscape

6:40 AM   |   19 June 2025

US AI Startups Continue to Attract Mega-Rounds in 2025: A Deep Dive into the Funding Landscape

US AI Startups Continue to Attract Mega-Rounds in 2025: A Deep Dive into the Funding Landscape

The artificial intelligence industry experienced a landmark year in 2024, characterized by unprecedented levels of investment and rapid technological advancements. According to TechCrunch's count, 49 US AI startups successfully closed funding rounds of $100 million or more in 2024 alone. This included three companies that secured multiple "mega-rounds" and seven that raised rounds valued at $1 billion or larger, underscoring a significant influx of capital into the sector. The question on many minds as 2025 began was whether this extraordinary momentum could be sustained.

As the first half of 2025 unfolds, the answer appears to be a resounding yes. The pace of investment in US-based AI startups raising substantial capital has not only continued but, in some key metrics, has accelerated. The first quarter of 2025 saw a higher number of AI mega-rounds closing in the U.S. compared to the same period in 2024, and multiple billion-dollar rounds have already been announced. This sustained investment highlights the enduring belief among venture capitalists and strategic investors in the transformative potential and commercial viability of AI technologies across a wide array of applications and foundational layers.

Mega-rounds, typically defined as funding rounds of $100 million or more, serve as a critical indicator of market confidence and the perceived scalability of a startup's technology and business model. For AI companies, these large infusions of capital are often essential to fuel intensive research and development, attract top-tier talent, acquire necessary computing resources (like expensive GPUs), and scale operations rapidly in a highly competitive global market. The prevalence of such large rounds in 2025 suggests that investors are betting on AI not just as a technological trend, but as the core engine for future economic growth and disruption.

This article provides a comprehensive overview of the US AI startups that have successfully raised $100 million or more in 2025, based on publicly reported data. By examining these deals, we can gain valuable insights into the specific areas within the AI landscape that are attracting the most significant investment, the types of solutions being prioritized, and the investors shaping the future of artificial intelligence.

The Continued Surge: A Look at the Numbers

The list of US AI startups hitting the $100 million funding mark in the first half of 2025 is diverse, spanning various applications and technological approaches. While a simple chronological list provides a snapshot, analyzing these deals thematically reveals deeper trends in the market. The investments reflect a focus on both the foundational layers of AI – the infrastructure, models, and tools necessary to build and deploy AI systems – and the application of AI to solve complex problems in specific industries.

The sheer volume of mega-rounds in just the first six months of the year is remarkable. As of mid-June 2025, at least 24 US AI companies have closed rounds of $100 million or more. This figure, while slightly lower than the full-year count for 2024, represents a robust pace, especially considering we are only halfway through the year. The fact that Q1 2025 outpaced Q1 2024 in mega-round closures suggests an acceleration in the early part of the year, potentially indicating growing urgency among investors to back promising AI ventures.

Furthermore, the valuations associated with many of these rounds are substantial, with several companies achieving multi-billion dollar status. This points to a market willing to assign high values to companies demonstrating strong potential in AI, whether through groundbreaking research, rapid user adoption, or clear paths to monetization in enterprise or consumer markets.

Key Investment Areas and Notable Deals

The mega-rounds of 2025 are flowing into several key areas within the AI ecosystem. These can broadly be categorized into AI Infrastructure, Foundational Models/Research, and AI Applications across various verticals.

AI Infrastructure and Hardware

Building and running advanced AI models requires immense computing power and specialized hardware. Several companies focused on providing this critical infrastructure have attracted significant investment:

  • TensorWave: This Las Vegas-based company, focused on AMD-powered AI cloud infrastructure, announced a $100 million Series A round on May 14. The round was co-led by Magnetar Capital and AMD Ventures, highlighting strategic interest from a major hardware player. This investment underscores the demand for diverse and powerful computing options beyond traditional providers.
  • Nexthop AI: An AI infrastructure company, Nexthop AI raised a $110 million Series A round announced on March 25. Led by Lightspeed Venture Partners, this early-stage mega-round indicates strong conviction in Nexthop's approach to building the underlying layers for AI.
  • Celestial AI: Focused on revolutionizing AI infrastructure with its photonic fabric technology, Celestial AI secured a $250 million Series C round on March 11, valuing the company at $2.5 billion. The round was led by Fidelity, with participation from notable investors like Tiger Global and BlackRock, signaling mainstream investor interest in next-generation AI hardware.
  • Together AI: This company, which develops open-source generative AI and AI model development infrastructure, raised a $305 million Series B round on February 20, achieving a $3.3 billion valuation. Co-led by Prosperity7 and General Catalyst, with participation from Nvidia and Salesforce Ventures, Together AI's funding highlights the importance of open platforms and tools for AI development.
  • Lambda: An AI infrastructure company providing cloud services and hardware, Lambda raised a $480 million Series D round announced on February 19, valuing the startup at nearly $2.5 billion. Co-led by SGW and Andra Capital, with participation from Nvidia and ARK Invest, Lambda's funding demonstrates the massive demand for scalable AI compute resources.
  • EnCharge AI: This AI hardware startup, focusing on accelerating AI using analog chips, raised a $100 million Series B round on February 13. Led by Tiger Global, the investment points to continued innovation and investment in specialized AI silicon designed for efficiency and performance.

The significant investment in these infrastructure companies reflects the foundational need for robust, accessible, and efficient computing power to support the burgeoning AI industry. As AI models become larger and more complex, the demand for advanced hardware and cloud platforms will only grow, making this a critical area for venture capital.

Foundational Models and AI Research

The development of large language models (LLMs) and other foundational AI models remains a central focus, attracting some of the largest rounds:

  • OpenAI: The AI behemoth closed a record-breaking $40 billion funding round on March 31, valuing the startup at an astounding $300 billion. Led by SoftBank with participation from Microsoft and Thrive Capital, this mega-mega-round solidifies OpenAI's position at the forefront of AI research and commercialization and highlights the massive capital required to compete at this level.
  • Anthropic: Another leading AI research and large language model company, Anthropic raised $3.5 billion in a Series E round announced on March 3, valuing the startup at $61.5 billion. Led by Lightspeed, this substantial round demonstrates continued investor confidence in Anthropic's approach to developing advanced and safe AI systems.
  • LMArena: While not a model developer itself, LMArena, the organization behind popular AI model benchmarking tools, raised a $100 million seed round on May 21, valuing the startup at $600 million. Co-led by Andreessen Horowitz and UC Investments, this investment highlights the growing importance of evaluation and transparency in the AI model ecosystem.

These investments underscore the ongoing race to build the most capable and versatile AI models. The valuations reflect the perceived market dominance and potential revenue streams associated with controlling key foundational AI technology.

AI in Specialized Applications

Beyond infrastructure and foundational models, AI is being applied to transform numerous industries. The 2025 mega-rounds show strong investment in vertical AI solutions:

Healthcare and Drug Discovery

  • Insilico Medicine: This company, leveraging generative AI for drug discovery, raised $110 million in a Series E round announced on March 13, valuing the company at $1 billion. Co-led by Value Partners and Pudong Chuangtou, this funding accelerates the use of AI to identify novel targets and design new molecules, potentially speeding up drug development.
  • Lila Sciences: Aiming to create a science superintelligence platform, Lila Sciences raised a $200 million seed round led by Flagship Pioneering. This substantial early-stage investment highlights the potential investors see in applying AI to fundamental scientific discovery.
  • Abridge: An AI platform that transcribes and summarizes patient-clinician conversations, Abridge was valued at $2.75 billion in a $250 million Series D round announced on February 17. Co-led by IVP and Elad Gil, this investment reflects the strong demand for AI solutions that can improve efficiency and documentation in healthcare settings.
  • Hippocratic AI: Developing large language models specifically for the healthcare industry, Hippocratic AI announced a $141 million Series B round on January 9, valuing the company at over $1.6 billion. Led by Kleiner Perkins with participation from Andreessen Horowitz and Nvidia, this funding targets the creation of safe and reliable AI agents for healthcare tasks.

The significant investment in AI for healthcare and drug discovery underscores the industry's potential to leverage AI for everything from administrative tasks and clinical documentation to accelerating the complex and costly process of discovering and developing new medicines.

Legal Tech

  • Eudia: An AI legal tech company, Eudia raised $105 million in a Series A round led by General Catalyst on February 13. This investment points to the growing adoption of AI tools within the legal profession to automate tasks, analyze documents, and provide insights.
  • Harvey: Another AI legal tech company, Harvey raised a $300 million Series D round announced on February 12, valuing the 3-year-old company at $3 billion. Led by Sequoia with participation from the OpenAI Startup Fund, Harvey's rapid rise and valuation highlight the perceived value of AI in enhancing legal workflows and decision-making.

The legal sector, traditionally reliant on manual processes, is ripe for AI-driven transformation. These investments indicate strong confidence in AI's ability to improve efficiency, accuracy, and access within legal services.

Enterprise AI and Productivity

  • Glean: An enterprise search startup leveraging AI, Glean continues its impressive fundraising trajectory with a $150 million Series F round announced on June 10, valuing the company at $7.25 billion. Led by Wellington Management, Glean's success demonstrates the strong enterprise demand for AI-powered tools that can help employees find information more effectively across disparate company systems.
  • Turing: An AI coding startup that partners with LLM companies, Turing closed a $111 million Series E round on March 7, valuing the startup at $2.2 billion. Led by Khazanah Nasional, Turing's funding highlights the critical role of AI in enhancing software development workflows and providing coding assistance.

AI's potential to boost productivity and efficiency within businesses is a major driver of investment. Companies like Glean and Turing are building tools that directly impact how employees work and access information.

Media Production and Creative AI

  • Runway: Known for creating AI models for media production, Runway raised a $308 million Series D round announced on April 3, valuing the company at $3 billion. Led by General Atlantic with participation from SoftBank and Nvidia, Runway's funding reflects the explosive growth and investment in generative AI tools for creative industries, particularly video generation.
  • ElevenLabs: A synthetic voice startup, ElevenLabs raised a $180 million Series C round announced on January 30, valuing the company at over $3 billion. Co-led by ICONIQ Growth and Andreessen Horowitz, ElevenLabs' success highlights the significant market for high-quality AI-generated audio content.

The creative industries are being rapidly reshaped by generative AI. Investments in companies like Runway and ElevenLabs demonstrate the strong belief that AI will become an indispensable tool for content creation, from video and audio to text and images.

Defense Technology

  • Shield AI: An AI defense tech startup, Shield AI raised $240 million in a Series F round that closed on March 6, valuing the company at $5.3 billion. Co-led by L3Harris Technologies and Hanwha Aerospace, this investment highlights the increasing integration of advanced AI into defense systems, particularly autonomous technologies like drones.

The application of AI in defense is a growing area, attracting significant investment from both traditional venture firms and strategic investors in the defense sector. Shield AI's funding underscores the push towards AI-powered autonomous capabilities.

Other Notable Areas

  • Anysphere: The AI research lab behind the AI coding tool Cursor, Anysphere raised a sizable $900 million Series C round on June 5, valuing the company at nearly $10 billion. Led by Thrive Capital, this investment in a coding-focused AI tool highlights the strong market demand for AI assistance in software development.
  • SandboxAQ: This company, which operates at the intersection of AI and quantum technology, closed a $450 million Series E round on April 4, valuing the company at $5.7 billion. The round included investors like Nvidia and Google, indicating interest in the long-term potential of combining AI with emerging technologies like quantum computing.
  • Reflection.Ai: Focused on building superintelligent autonomous systems, this Brooklyn-based company raised a $130 million Series A round on March 7, valuing the 1-year-old company at $580 million. Led by Lightspeed Venture Partners and CRV, this early-stage mega-round points to speculative investment in ambitious, long-term AI goals.

Investor Landscape and Trends

The list of investors participating in these mega-rounds reads like a who's who of the venture capital world, alongside significant corporate and strategic investors. Firms like Lightspeed Venture Partners, Andreessen Horowitz, Sequoia, General Catalyst, Kleiner Perkins, Thrive Capital, and SoftBank appear multiple times across different deals, indicating their strong focus and conviction in the AI sector. Corporate investors like Nvidia (participating in Runway, Together AI, Lambda, Hippocratic AI, SandboxAQ) and AMD Ventures (participating in TensorWave) are also highly active, often investing in companies that complement their core hardware or software businesses.

The participation of investors like BlackRock and Tiger Global in Celestial AI, and Wellington Management in Glean, suggests that AI mega-rounds are increasingly attracting later-stage and public market-focused investors, viewing these companies as future market leaders. The presence of strategic investors in defense (L3Harris Technologies, Hanwha Aerospace in Shield AI) and healthcare (implied by the focus of Abridge and Hippocratic AI) highlights the industry-specific adoption and integration of AI.

A notable trend is the speed at which some companies are achieving high valuations. Reflection.Ai, just one year old, secured a $130 million Series A at a $580 million valuation. Harvey, three years old, reached a $3 billion valuation with its Series D. Anysphere, behind the Cursor coding tool, hit nearly $10 billion with its Series C. This rapid value appreciation reflects the intense competition for promising AI startups and the perceived winner-take-all dynamics in certain AI niches.

The continued flow of capital into AI, particularly in large rounds, suggests that investors are prioritizing growth and market position over immediate profitability in many cases. The focus remains on building dominant platforms and technologies that can capture significant market share as AI becomes more integrated into the economy.

Implications for the AI Ecosystem

The sustained pace of mega-rounds in 2025 has several implications for the AI ecosystem:

  • Accelerated Development: Large funding rounds provide startups with the resources needed to accelerate R&D, hire top talent, and invest in the expensive compute infrastructure required for advanced AI. This can lead to faster technological progress and quicker deployment of new AI capabilities.
  • Increased Competition: High levels of investment fuel intense competition among startups vying for market leadership. This competition can drive innovation but also leads to high burn rates and pressure to achieve rapid growth.
  • Talent Wars: The influx of capital exacerbates the competition for skilled AI researchers and engineers, driving up salaries and making talent acquisition a critical challenge for startups.
  • Market Consolidation: While the focus is on growth, the high valuations and competitive landscape could eventually lead to consolidation, with larger tech companies or well-funded startups acquiring smaller players.
  • Focus on Real-World Applications: While foundational models receive massive investment, the significant funding in areas like healthcare, legal tech, and enterprise AI highlights the increasing focus on applying AI to solve concrete, high-value problems in specific industries.

The comparison to 2024, a year already considered monumental for AI funding, indicates that 2025 is shaping up to be another period of significant growth and investment. The fact that Q1 2025 saw more mega-rounds than Q1 2024 suggests that the funding environment remains highly favorable for AI companies demonstrating traction and potential.

Challenges and Future Outlook

Despite the optimistic funding landscape, challenges remain. The high valuations raise questions about future returns and potential market corrections. Regulatory scrutiny around AI is increasing globally, which could impact development and deployment. Ethical considerations, such as bias in AI models and job displacement, also require careful navigation.

Nevertheless, the fundamental drivers of AI investment remain strong. The potential for AI to increase productivity, drive scientific discovery, create new forms of media, and solve complex societal challenges continues to attract capital. The investments in 2025 reflect a belief that we are still in the early to middle stages of the AI revolution, with significant opportunities for growth and value creation.

Looking ahead, the pace of investment will likely continue to be influenced by technological breakthroughs, market adoption rates, and the broader economic climate. However, the strong start to 2025, marked by numerous mega-rounds across diverse AI sectors, suggests that the AI funding boom is far from over. Investors are clearly eager to back the companies they believe will define the next era of artificial intelligence.

List of US AI Startups with $100M+ Rounds in H1 2025

For reference, here is the list of US AI companies that have publicly announced funding rounds of $100 million or more in the first half of 2025, as compiled from various reports:

June

  • Glean: $150 million Series F at $7.25 billion valuation (Enterprise Search) - TechCrunch Report
  • Anysphere (Cursor): $900 million Series C at nearly $10 billion valuation (AI Coding Tool/Research) - TechCrunch Report

May

  • Snorkel AI: $100 million Series D at $1.3 billion valuation (AI Data Labeling) - BusinessWire Report
  • LMArena: $100 million Seed at $600 million valuation (AI Benchmarking) - TechCrunch Report
  • TensorWave: $100 million Series A (AI Cloud Infrastructure) - TechCrunch Report

April

  • SandboxAQ: $450 million Series E at $5.7 billion valuation (AI & Quantum Tech) - SandboxAQ Press Release
  • Runway: $308 million Series D at $3 billion valuation (AI Media Production) - TechCrunch Report

March

  • OpenAI: $40 billion round at $300 billion post-money valuation (AI Research & Models) - TechCrunch Report
  • Nexthop AI: $110 million Series A (AI Infrastructure) - Nexthop AI Press Release
  • Insilico Medicine: $110 million Series E at $1 billion valuation (AI Drug Discovery) - PRNewswire Report
  • Celestial AI: $250 million Series C at $2.5 billion valuation (AI Infrastructure) - Celestial AI Blog
  • Lila Sciences: $200 million Seed (Science Superintelligence Platform) - Lila Sciences News
  • Reflection.Ai: $130 million Series A at $580 million valuation (Autonomous Systems) - The SaaS News Report
  • Turing: $111 million Series E at $2.2 billion valuation (AI Coding) - TechCrunch Report
  • Shield AI: $240 million Series F at $5.3 billion valuation (AI Defense Tech) - TechCrunch Report
  • Anthropic: $3.5 billion Series E at $61.5 billion valuation (AI Research & Models) - TechCrunch Report

February

  • Together AI: $305 million Series B at $3.3 billion valuation (AI Infrastructure) - Together AI Blog
  • Lambda: $480 million Series D at nearly $2.5 billion valuation (AI Cloud Platform) - Lambda Labs Blog
  • Abridge: $250 million Series D at $2.75 billion valuation (AI Healthcare Documentation) - Abridge Press Release
  • Eudia: $105 million Series A (AI Legal Tech) - Eudia Blog
  • EnCharge AI: $100 million Series B (AI Hardware/Analog Chips) - TechCrunch Report
  • Harvey: $300 million Series D at $3 billion valuation (AI Legal Tech) - Harvey Blog

January

  • ElevenLabs: $180 million Series C at over $3 billion valuation (Synthetic Voice) - TechCrunch Report
  • Hippocratic AI: $141 million Series B at over $1.6 billion valuation (Healthcare LLMs) - TechCrunch Report

This list, while based on publicly reported data and subject to updates, provides a clear picture of the significant capital flowing into the US AI startup ecosystem in 2025. The breadth of applications and the scale of investment highlight the continued confidence in AI as a transformative technology driving innovation across industries.