AI Overviews now appears on the majority of US Google informational queries, and third-party studies through 2025 measured organic click-through rate drops in the 30-40% range on impacted SERPs for many publishers. That click-through collapse is the backdrop for every funding round in this 21-startup category. Perplexity ($2.05B Series F, ~$14B valuation reported in 2024-25) and Glean ($750M Series F) account for nearly 70% of the $4.02B in disclosed AI Search funding. Six rounds in the trailing 12 months averaged $252M — among the highest on the platform.
Perplexity vs the SERP
Perplexity's bet is that cited, focused answers without ad-driven ranking beat AI Overviews on trust and depth. The counter-bet is distribution: Google still owns the query origin point, and AI Overviews is free at the moment of intent. Perplexity's pivot to Pro and Enterprise tiers, the Comet browser launch, and partnerships with publishers exist because consumer ad-supported answer-engine economics don't pencil out against a free in-SERP alternative. You.com ($75M Series B) targets the productivity-search niche; Phind ($12M seed) defends developer queries with deeper code citations.
The retrieval layer pays regardless
Whoever wins the consumer fight, the agents and RAG applications underneath need indexing. Chroma ($20.3M seed) and Marqo ($19.4M Series A) ship vector and hybrid retrieval primitives developers integrate directly. Exa ($17M Series A) indexes the web specifically for AI applications with semantic search and structured outputs that LLM agents consume. Tavily ($25M Series A) does real-time agent-grade web extraction. Twelve Labs ($77M Series B) covers video understanding for searchable multimodal corpora. These are the rounds that don't depend on Perplexity's outcome — every agent, copilot, and enterprise search product needs them.
Vertical search defends margin
OpenEvidence ($735M Series D) is the standout: clinicians query it like a search engine, and the trust signal of curated medical literature is hard for horizontal answer engines to displace. Elicit ($9M seed) plays the same role for scientific research. Glean's $750M defends the in-organization RAG layer — Slack plus Drive plus Notion plus SaaS connectors plus a single answer surface — against Microsoft Copilot bundling. The vertical and enterprise plays look more durable in 2026 than the horizontal consumer answer-engine seat.