VC Funding Top Ten — September 8, 2026: AI Mega-Rounds, Nuclear IPO, European Space

Overview

Tuesday afternoon, September eighth—today's biggest check is a staggering two billion dollars for AI agent developer Cognition. That deal alone accounts for nearly a third of the day's total disclosed funding, which topped six and a half billion dollars across just ten rounds. The theme is clear: massive, concentrated

In this show

• Tuesday afternoon, September eighth—today's biggest check is a staggering two billion dollars for AI agent developer Cognition. That deal alone accounts for nearly a third of the day's total disclosed funding, which topped six and a half billion dollars across just ten rounds. The theme is clear: massive, concentrated bets on foundational AI and the energy to power it. We'll break it all down with our Markets and World analysts. Let's get into the numbers.
• Here is today's snapshot. Total disclosed funding hit $6.58 billion. The largest round belongs to Cognition, which raised $2 billion at a $48 billion valuation. AI was the hottest category, with four of the top ten deals. And in the public markets, a notable IPO from Holtec Nuclear, which raised $900 million at a $10.2 billion valuation. The story of the day is the torrid pace of AI funding, with mega-rounds for Cognition and Mistral AI totaling a combined $5.5 billion.
• At number one, Cognition's $2 billion Series E was co-led by Andreessen Horowitz and Accel, pushing its valuation to a massive $48 billion. The company develops 'Devin,' an autonomous AI software engineering agent. The key takeaway here is the velocity: this round doubles the company's valuation from its $1 billion Series D just four months ago. It's a clear signal of intense investor demand for AI agents that can fully automate complex software development.
• Coming in at number two is Europe's AI champion, Mistral AI. The Paris-based company raised a $3.5 billion Series D led by Samsung Electronics, reaching a $24 billion valuation. Mistral develops and sells foundational large language models, positioning itself as a key global competitor to US-based providers. This funding nearly doubles Mistral's valuation in less than a year, solidifying its status as Europe's most valuable AI startup and a strategic asset for the continent.
• The third largest deal today was an IPO. Holtec Nuclear raised $900 million in its public market debut, commanding a $10.2 billion valuation. Underwriters included J.P. Morgan and Goldman Sachs. Holtec specializes in nuclear technology, from spent fuel storage to developing small modular reactors, or SMRs. This is a huge moment for the resurgent nuclear power sector, which is seeing a surge in interest driven by the massive and growing energy demands from AI and data centers.
• At number four, we cross back to Europe for The Exploration Company, a space logistics startup. It raised a $450 million Series C at a $2 billion valuation, with Bessemer Venture Partners and Atomico leading. The company is developing 'Nyx,' a reusable space capsule designed for cargo and eventually crew transport to low Earth orbit. This funding is critical for accelerating a sovereign European reusable space capsule, a key piece of infrastructure for the continent's ambitions in space.
• In cybersecurity, Cylake secured a $245 million convertible note led by Lightspeed Venture Partners. Founded by a Palo Alto Networks veteran, Cylake is building an AI-native cybersecurity platform specifically for on-premises or private cloud environments. This is a direct play for highly regulated organizations in finance, healthcare, and government that require full data sovereignty and cannot use public cloud security solutions. It's a massive, underserved market.
• Number six is Forus, a health-tech company, raising a $150 million Series C from Bain Capital Ventures, which pushed its valuation to $3 billion. Forus uses an AI-powered platform to automate the frustrating process of getting prescription medications, handling things like insurance approvals and financial aid. The takeaway? This round tripled the company's valuation in just four months, showing immense traction for its solution to the administrative friction in the drug supply chain.
• In biotech, BrainChild Bio lands at number seven with a significant $116 million Series A from an undisclosed family fund. This clinical-stage company is developing CAR T-cell therapies for central nervous system tumors. The funding is earmarked for a pivotal Phase 2 trial for a devastating and rare pediatric brain cancer that currently has very few treatment options. It's a large, high-impact round for such an early stage, signaling strong conviction in the science.
• At number eight is another biotech, Moonwalk Biosciences, raising a $70 million Series B co-led by Alpha Wave. The company is developing RNA interference medicines for obesity, specifically targeting adipose tissue. What makes this deal notable is the strategic participation from pharma giant Eli Lilly. The funding will move Moonwalk's lead candidate into human trials. The goal is a drug that reduces weight while preserving lean muscle mass, a key challenge in current obesity treatments.
• Rounding out the top ten are two large seed rounds. At number nine, Bluecore Energy raised a hefty $50 million seed to develop small, water-cooled nuclear reactors on floating barges. The goal is to provide mobile, zero-emission power to ports and data centers. And at number ten, Cloverleaf Bio raised an oversubscribed $33 million seed round led by 4BIO Capital. The company is developing a new class of RNA-based cancer treatments, and attracted investments from the venture arms of AbbVie, Lilly, and Boehringer Ingelheim.
• And the one thing to watch: the Nuclear Renaissance goes public. Holtec Nuclear's successful $900 million IPO today is the latest signal of strong public market appetite for nuclear energy. With AI's power demands straining grids, expect to see more private nuclear tech companies, especially those in the small modular reactor space, test the public markets. The performance of Holtec will be a key bellwether for this capital-intensive but increasingly critical sector. We'll be back tomorrow afternoon at three PM Pacific with the next deal flow.