The Year AI Ate Venture Capital
In 2025, AI startups consumed an unprecedented share of venture capital. Fifty-five US AI companies raised rounds of $100 million or more, totaling approximately $56 billion in funding. AI accounted for roughly 50-53% of all venture capital investment for the year. A concentration of capital in a single technology category that has no precedent in the history of venture financing.
The scale of individual rounds was staggering. OpenAI raised $40 billion in March 2025, representing over 70% of the total. Even excluding that outlier, the remaining 54 companies raised $16 billion, with an average round size of roughly $296 million. This is not seed funding for speculative bets. This is growth capital for companies building real products with real revenue, deployed at a pace that reflects genuine conviction about AI's near-term commercial potential.
The Mega-Rounds: $1 Billion and Above
Four companies dominated the fundraising leaderboard. OpenAI's $40 billion round valued the company at approximately $300 billion, making it the most valuable private company in history. The round included investment from Microsoft, SoftBank, and a consortium of sovereign wealth funds, and the capital is earmarked for compute infrastructure and AGI research.
Anthropic raised $13 billion in its Series F round in September 2025, reaching a $183 billion valuation. The company, which makes the Claude family of models, has positioned itself as the safety-focused alternative to OpenAI. The round was led by Google and included Amazon, which has committed billions in total investment to Anthropic through a combination of equity and cloud computing credits.
Project Prometheus launched with $6.2 billion in initial funding, one of the largest day-one raises for any AI company. xAI, Elon Musk's AI venture, pulled in $5.3 billion in equity funding during 2025, building the Grok series of models and its Colossus GPU cluster.
The Surprise: Cursor's $2.3 Billion
The most remarkable round of 2025 may have been Anysphere's. The parent company of the AI code editor Cursor. In November 2025, the company raised $2.3 billion in Series D financing at a $29.3 billion post-money valuation. For a company whose primary product is a VS Code fork with AI features, this valuation signals extraordinary investor confidence in the AI-native developer tools market.
Cursor's metrics justify some of the enthusiasm. The product had grown to millions of monthly active developers by the time of the raise, and its revenue trajectory was on track to exceed $500 million ARR. The round reflects a bet that AI code editors will become the primary interface for software development, and that the company that captures that position will own one of the most valuable software categories.
Enterprise AI Infrastructure: The Largest Cluster
Enterprise AI and infrastructure companies formed the largest group among the $100M+ raises. This category includes companies building the picks-and-shovels of the AI industry: model serving platforms, GPU cloud providers, data labeling services, AI security tools, and enterprise deployment platforms.
Scale AI expanded its defense contracts, securing a five-year, $100 million Department of Defense agreement that includes physical SCIF infrastructure and security clearances. CoreWeave, the GPU cloud provider, raised multiple rounds totaling several billion dollars as demand for AI compute infrastructure remained strong. Together AI, which provides model serving and fine-tuning infrastructure, raised over $100 million to expand its platform.
The infrastructure category is where the most durable businesses are being built. While application-layer AI companies face competition from the model providers themselves, infrastructure companies sell to everyone. Including the model providers. This competitive dynamic makes infrastructure the most defensible position in the current AI landscape.
The Application Layer: Vertical AI Wins
The most interesting application-layer raises were in vertical AI. Companies applying AI to specific industries rather than building general-purpose tools. Healthcare AI companies raised heavily, with multiple rounds above $200 million for companies building clinical decision support, drug discovery, and medical imaging analysis. Legal AI, financial AI, and defense AI each saw multiple $100M+ rounds.
The pattern is clear: investors are betting that the winning AI applications will be deeply integrated into specific industry workflows, not general-purpose chatbots. Companies that combine AI capability with domain expertise and regulatory knowledge are commanding premium valuations because their moats are deeper than pure technology.
Early 2026 Signals
The pace has not slowed in 2026. xAI secured $20 billion in Series E funding in the first weeks of the year. LMArena, a platform for evaluating AI models, raised $150 million at a $1.7 billion valuation. The signal is that institutional investors remain aggressively bullish on AI, and the check sizes continue to grow.
However, the concentration of capital in a small number of companies is noteworthy. The top 5 raises in 2025 accounted for over 85% of the total capital deployed. The long tail of AI startups raising $100-500 million faces a very different fundraising environment than the frontier model companies raising billions. For these companies, demonstrating real revenue and clear paths to profitability is becoming essential as investors grow more selective.
Sources and Signals
Funding data from TechCrunch, Crunchbase, and Eqvista tracking of US AI startup raises. Valuation data from published round announcements and investor disclosures. Market analysis from Crunchbase year-end venture capital reports. Enterprise category analysis from Seven Square Tech and AI Certs industry coverage.
