Series B post-money benchmarks

Cap-table mechanics at this stage

Series B has seen sharp 2024-26 compression for non-AI startups. AI bifurcation persists and widens from Series A: Carta's AI Series B premium is roughly +50% (AI pre-money on the order of $143M). Option pool refreshes at this stage typically smaller than Series A; existing pool is usually still meaningful.

Typical post-money breakdown

For a series b round at the cohort median ($200M post-money, average check 32.5M, 10% option pool refresh): new investor takes roughly 16.3% of post-money. Option pool refresh of 5-10% of post-money consumes additional founder + existing-investor allocation. Existing holders absorb the dilution proportionally.

AI-labelled series b rounds price about +50% above non-AI on Carta's broad AI cohort. AI Series B post-money median: approximately $300M. Within AI the gap is larger still — foundational-model companies command multiples of application-layer peers. The cap-table implication: AI rounds have higher absolute valuations but similar dilution percentages, so the absolute dollar value of the new investor's stake is materially higher.

Source

Source: Carta Q4 2025 + PitchBook-NVCA Q1 2026 · Verified 2026-08-31.