Series B
Series B dilution lighter (15-20%) because option pools refresh smaller. Down rounds at Series B are increasingly common for non-AI startups in 2026 — anti-dilution provisions on Series A preferred kick in here.
The full distribution
Series B post-money valuations vary widely. Median is $200M but the P25-P75 range spans $100M to $380M — a 3.8x spread between the bottom-quartile and top-quartile deal. For founders, this means there's genuine room to negotiate up if your story is strong; the median is just the middle, not a ceiling.
Check size and option pool
Series B round checks typically range $15M to $50M. Option pool refresh is typically 5-10% of post-money. The option pool comes out of pre-money allocation, not post-money — so a 10% pool refresh on a $$150M pre-money is essentially $$15.0M of founder dilution that doesn't fund anything operational.
AI-labelled series b rounds in 2026 transact at +70% over non-AI deals at the same stage. AI Series B pre-money median is approximately $255M vs $150M for non-AI. If you're non-AI, strip AI deals out of your comparable benchmarks before using a comp-based valuation method — otherwise the inflated comp set will produce an unrealistic anchor that VCs will reject. See the AI premium deep-dive.
Source
↗ https://carta.com/data/state-of-private-markets-q4-2025/Source: Carta Q4 2025 + PitchBook-NVCA Q1 2026 · Verified 2026-06-03.