Billion-Dollar VC Rounds Now Gobble Up 73% of All US Startup Funding

The Megadeal Tipping Point

The venture capital ecosystem has quietly passed a landmark: in 2026 so far, 73% of all US startup funding has flowed into rounds of $1 billion or more. That’s $290 billion across just 23 known deals, according to Crunchbase data, and the year is only half over. By contrast, billion-dollar-plus rounds were an anomaly as recently as the mid-2010s.

The sheer scale of the shift is hard to overstate. Even the record-shattering year of 2025 — when OpenAI closed a $40 billion financing — saw total annual deal count for megadeals reach 23. Now, in fewer than eight months, 2026 has already matched that number, with five months still to go. The frequency is accelerating, and the average size is swelling.

Two AI companies are behind a huge chunk of this year’s totals, reinforcing a pattern where the most capital-hungry sectors (chiefly artificial intelligence) are concentrating funding into a handful of enormous bets. The trend marks a departure from the broader early-stage and mid-sized rounds that historically defined venture capital.

The first billion-dollar round in startup history was Uber’s $1.2 billion Series D in 2014. Over the next few years a small club of companies — including SpaceX, Airbnb, WeWork, Argo AI, Grail and Fanatics — joined the ten-figure club. Their post-deal trajectories have been wildly uneven: SpaceX’s recent implied valuation reached $1.6 trillion, while WeWork and Argo AI collapsed. That mixed history now haunts a market where giant rounds are becoming the default, not the exception.

Why Giant Rounds Are Reshaping Venture Capital

AI’s Insatiable Capital Appetite

The current megadeal wave is inseparable from the race to build and train artificial intelligence. Large language models and the infrastructure to run them demand capital on a scale previously reserved for chip fabrication plants or entire energy projects. Two unnamed AI leaders (Crunchbase’s data references them as the drivers of this year’s bulge) consumed such large shares of the $290 billion total that they single-handedly elevated the 73% figure. This concentration means that VC as an asset class is increasingly a bet on a handful of AI juggernauts, rather than a diversified portfolio of disruptive startups.

A Mixed Bag for Earlier Megadeal Recipients

History offers a cautionary note. Of the earliest billion-dollar-round recipients, many went on to public markets at enormous valuations — Uber ($148 billion), Airbnb ($87 billion) and SpaceX (over $1.6 trillion on secondary markets) — delivering outsized returns. But two highly hyped recipients, Argo AI and WeWork, imploded, while cancer diagnostics firm Grail has swung between highs and lows. Even among the survivors, the path from mega-round to mega-exit is not assured, and the failures often leave painful dilution for employees and earlier investors. This record underscores that massive capital injections are no guarantee of durable business models.

The Concentration Risk for Limited Partners

For the institutions that back venture funds — pension funds, endowments, sovereign wealth funds — the megadeal era reshapes risk. When three-quarters of deployed capital lands in just a few dozen companies each year, the traditional venture portfolio strategy of spreading bets across hundreds of startups gets inverted. A bad year for two or three names could cause fund-level losses, while the upside intensifies if those bets pay off. This environment rewards top-tier VCs with access to the most coveted AI deals and sidelines managers who cannot write large enough cheques. It also raises the stakes for due diligence: choosing which AI leader to back may soon matter more than the aggregate number of investments a fund makes.

What the Megadeal Era Means for Founders and Investors

For startup founders

• If you are in AI or other capital-intensive fields, the funding environment for very large rounds is historically favourable. But recognise that raising at a $10B+ valuation brings immense pressure to deliver unicorn-plus exits — and that the graveyard of overcapitalised companies (WeWork, Argo AI) is real.
• Early-stage founders outside AI should expect a tougher time competing for attention and LP dollars. Emphasise capital efficiency and clear paths to profitability to differentiate from the megadeal narrative.

For venture investors

• The concentration of capital into a handful of AI giants means deal selection is now the single most important lever for fund returns. Miss the winner, and even a large portfolio of smaller bets may not compensate.
• Secondary market pricing of earlier megadeal recipients (SpaceX, Uber, Airbnb) suggests that the late-stage mega-round can still work, but only if the company reaches category-defining scale. Be cautious about extending the AI funding logic to sectors where the addressable market is not equally vast.

For limited partners

• With 73% of US VC dollars going to billion-dollar-plus rounds, assess your fund managers’ access to the top tier of AI deals. A manager who cannot write a $500M cheque may be structurally excluded from the most attractive mega-rounds.
• Request scenario analysis showing how a 50% write-down of the two largest positions in a fund would impact overall returns. Portfolio construction assumptions built in the pre-2020 era may no longer hold.