Mega-rounds (US$100m+) in venture capital

What it is

A mega-round is a venture capital financing of US$100m or more closed in a single transaction. No regulatory or legal definition exists; the label is imposed by data providers including PitchBook and CB Insights, and has become the standard industry shorthand for tracking capital concentration at the top of the market.

The principal investors in mega-rounds today are large US venture partnerships (Andreessen Horowitz, Sequoia Capital, Lightspeed Venture Partners), growth-stage crossover funds (Tiger Global, Coatue Management, D1 Capital), sovereign wealth funds from the Gulf (Saudi Arabia's Public Investment Fund and Abu Dhabi's Mubadala), Asian sovereign vehicles (SoftBank, Singapore's Temasek and GIC), and corporate strategics including Microsoft, Nvidia, and Amazon. The United States accounts for roughly half of global mega-round activity by value.

History

Nine-figure rounds were exceptional before 2013. Uber's US$363m Series C that year marked a structural shift toward growth-stage financing at scale. By 2015 the United States logged 100 or more mega-rounds in a single calendar year for the first time. SoftBank's US$100bn Vision Fund, closed in May 2017 with anchor commitments from Saudi Arabia's Public Investment Fund (US$45bn), SoftBank Group (US$28bn), and Abu Dhabi's Mubadala (US$15bn), normalised billion-dollar-plus cheques to individual startups, writing large positions in WeWork, Uber, and Didi over the following two years.

Mega-rounds peaked at 859 globally in 2021, during the near-zero interest rate environment. As the US Federal Reserve raised rates from near zero to over 5% between 2022 and 2023, venture deal-making contracted sharply. Globally, mega-rounds fell to 529 in 2022, then to 258 in 2023, a decline of 70% from the 2021 peak in two years. A recovery began in 2024 with 384 deals, driven almost entirely by investment in artificial intelligence companies.

Current state

As of mid-2026, mega-rounds have rebounded to levels that exceed the 2021 peak in dollar terms, though not in deal count. CB Insights recorded 738 mega-rounds globally in 2025, representing US$307bn, or 65% of total venture funding, on fewer than 3% of all deals. The US National Venture Capital Association's 2026 Yearbook counted 487 US mega-deals, accounting for 67% of US deal value; excluding those, the remaining roughly 14,865 US deals averaged US$7.1m each.

AI infrastructure companies have driven this concentration. The top five US AI companies by capital raised in 2025, OpenAI, CoreWeave, xAI, Anthropic, and Databricks, collected nearly US$60bn collectively. OpenAI's US$122bn financing closed in Q1 2026, the largest single private-company round on record globally. Excluding the five largest US deals in Q1 2026, aggregate US funding fell by more than 73%, illustrating how dependent headline figures are on a very small number of companies.

Relationships

Mega-rounds connect several distinct beats within this graph. In AI infrastructure, Together AI's US$800m Series C and AI tooling companies Baseten and TwelveLabs illustrate how compute-adjacent startups command capital previously reserved for late-stage unicorns. Defence technology is a second concentration point: US defense-tech companies set funding records in 2025 and 2026, with manufacturers such as Mach Industries clearing US$100m at Series C. Enterprise software shows that high-growth, revenue-generating companies can also access mega-round scale, as with Ramp's Series F. Gulf sovereign wealth funds appear as lead or anchor investors across all three clusters.

What to watch

The central variable is whether the US initial public offering market reopens consistently, allowing investors in 2021-era mega-rounds to exit above their entry valuations. As of mid-2026 the IPO window remains narrow. A second variable is geopolitical: Saudi Arabia's Public Investment Fund and Abu Dhabi sovereign vehicles are lead or anchor investors in a growing share of US AI and defense-technology mega-rounds, a concentration drawing scrutiny from the Committee on Foreign Investment in the United States (CFIUS). The European Union's AI Act and antitrust authorities are separately examining whether concentrated capital in a handful of companies creates durable market-structure risks. A third pressure is valuation discipline: seed-stage AI companies receiving US$100m to US$200m at formation, a category previously unheard of, face the sharpest markdown risk if the AI infrastructure buildout slows before revenue catches up with capital raised.