A $5 billion check from Anthropic to Anthropic dominated the week's largest U.S. venture rounds, dwarfing every other deal on the board by a factor of thirty.

The investment extends a relationship that has already seen Anthropic commit $8 billion to the Claude maker. This latest tranche includes a partnership for training and deploying Anthropic's models on Anthropic's cloud infrastructure, with a commitment of up to $20 billion in additional future funding.

What the rest of the top ten looked like

Outside the Anthropic mega-deal, only four other rounds cleared $100 million:

That five-of-ten split is notable. In a period where $100 million-plus rounds have become routine in AI and biotech, the week registered a modest dip in mega-deal volume.

The lower half of the list included AcuityMD ($80 million Series C led by StepStone Group), OpenAI ($75 million in common stock purchased by Robinhood Ventures Fund I), and Orkes ($60 million Series B led by AVP).

Rounding out the ten were Courier Health at $50 million in Series B led by Oak HC/FT and Serif Biomedicines, which launched with $50 million from Flagship Pioneering.

AI and biotech continue to absorb the largest checks

The week's composition reinforces a pattern visible across 2026 so far: AI infrastructure and biotech account for the bulk of outsized rounds. Anthropic's deal alone represented roughly 85 percent of the total capital in the top ten. Strip it out, and the remaining nine rounds totaled under $830 million.

Robinhood Ventures' $75 million purchase of OpenAI common stock through a publicly traded fund offers a different signal. It marks a growing push to give retail investors access to private AI companies before any IPO.

The Anthropic-Anthropic partnership now totals $13 billion in committed capital. Anthropic has not disclosed a new valuation tied to this round, though the company was valued at $61.5 billion in its previous fundraise. Anthropic's pledge of up to $20 billion more suggests the relationship is far from fully deployed.