Series B
Definition
Series B is the funding round that follows Series A, typically raised once a startup has clear product-market fit and a repeatable go-to-market motion, and needs capital to scale that motion rather than find it.
What is a Series B Round? How It Differs From Series A
Where Series A investors are betting you'll find a scalable way to grow, Series B investors expect you to already have one and are funding you to pour capital into it, more sales hires, more marketing spend, new market or product-line expansion.
What Series B investors look for: consistent revenue growth, often 2-3x year over year, an NRR above 100% showing existing customers expand rather than churn, and a CAC payback period under 12-18 months proving the GTM motion is efficient, not just fast.
Typical range as of the mid-2020s: $15-50 million raised at post-money valuations roughly in the $50-150 million range, though these numbers move a lot with market conditions and vary sharply by sector. ARR expectations for B2B SaaS Series B companies are commonly in the $3-10 million range, though this bar has risen since the 2021 funding peak as investors price rounds more conservatively.
The step-up in scrutiny between A and B is real: Series A investors will fund a strong team and an early signal, Series B investors want to see the metrics, not just the story. Walking into Series B conversations without clean cohort data, NRR, and CAC payback numbers is the most common reason good companies get a slower process than they expected.
Examples
A startup raises a $4M Series A at $16M pre-money to find product-market fit. Eighteen months later, with $4M ARR growing 150% year over year and 115% NRR, it raises a $25M Series B at a $90M pre-money valuation to scale the sales team that's already working.