Investors expecting Series B capital to be swallowed almost entirely by AI may find the current data counterintuitive. While AI continues to permeate deal flow, the market’s real story is its breadth: capital is spreading across sectors with far more balance than the prevailing narrative suggests. This diversity is not a footnote but a structural signal, especially for those evaluating mid‑stage allocations. It widens the aperture for opportunity identification and challenges the assumption that differentiated exposure at this stage must hinge on AI concentration.
Healthcare and biotech now account for more than a quarter of all Series B rounds over the last six months, eclipsing expectations and marking the most robust non‑AI share of the cycle. The average Series B has climbed to a record $68 million in 2026, reflecting investors’ willingness to double down on companies with validated models and visible paths to scaling. Deal counts, meanwhile, have held steady—avoiding the contraction seen in later stages—underscoring mid‑stage resilience even as capital becomes more selective. Sub‑$10 million Series B rounds have collapsed from roughly 150 per year to just 44, a shift that signals a market focused on fewer but stronger contenders. AI remains part of the picture, but its impact is distributed across verticals rather than concentrated into a single monolithic category.
For investors, this reinforces Series B as a traction‑driven inflection point: less speculative than earlier stages but offering more structural diversification than late‑stage mega‑rounds. The spread of activity beyond AI creates room for differentiated positions in sectors where fundamentals, not narratives, are pulling in capital. At the same time, rising round sizes raise the bar for participation, favoring investors prepared to commit at scale. For those recalibrating portfolio exposure, the message is clear: the most compelling mid‑stage opportunities may lie in places the AI‑centric storyline has obscured.
