Series B funding serves as a barometer for the startup landscape, marking the stage where startups are no longer nascent but are still high-risk, offering both significant upside and the real possibility of failure. According to Crunchbase’s data-driven overview spanning the past decade, the annual count of Series B deals in the U.S. has remained relatively stable—generally between 600 and 900 per year—except for a notable spike during the 2021-2022 market boom. This contrasts sharply with seed-stage rounds, which frequently exceed 8,000 annually, emphasizing the much more selective nature of Series B investing.
While the volume of Series B deals exhibits consistency, the total investment allocated to these rounds has experienced more dramatic fluctuations. Funding at this stage peaked in 2021, before falling by almost half the following year—a pattern clearly reflecting broader macroeconomic trends and capital market cycles. Despite these swings, the proportion of venture dollars directed to Series B rounds has stayed fairly stable for most of the past decade. The exception in 2025 is attributed to an unprecedented late-stage investment for OpenAI, which distorted proportions in the early part of the year. Generally, about one out of every several venture dollars goes to Series B companies, reinforcing the continued importance of this stage, even during periods of market turbulence.
Investor preferences at Series B have evolved significantly. In the early 2010s, large consumer-facing companies—like Uber and Airbnb—were frequent recipients of supergiant Series B rounds. However, recent years have seen a decisive pivot toward sectors such as Artificial Intelligence, clean energy, and industry-focused technologies. The largest Series B investment this year went to Together AI, a generative Artificial Intelligence cloud platform, while other standout rounds included residential energy and clean iron producers. Notably, the number of Series B rounds exceeding $100 million peaked in 2021 and has since declined. Meanwhile, the inherent selectiveness of Series B persists: only around half of startups that receive Series A funding make it to Series B, and just a small minority of those ultimately deliver standout returns.
