Y Combinator now runs four batches a year, and in 2026 those four batches produced 484 of the 513 AI startups in our database. Compared side by side, the batches have personalities: what founders chose to build shifted noticeably between Winter and Fall. This page puts the four intakes in one table.
1. The four batches, split by top categories
Summer 2026 is the giant: 173 AI companies, more than Winter and Spring combined. Fall follows at 149, Winter at 83 and Spring at 79. Agents and vertical AI lead every batch, but the chasing pack rotates: robotics surges in Summer (23 of the year's 51), devtools surge in Fall (24 of 58).
| Batch | AI startups | Agents | Vertical AI | DevTools | Robotics |
|---|---|---|---|---|---|
| YC Winter 2026 | 83 | 28 | 29 | 7 | 5 |
| YC Spring 2026 | 79 | 36 | 16 | 10 | 6 |
| YC Summer 2026 | 173 | 37 | 59 | 17 | 23 |
| YC Fall 2026 | 149 | 36 | 45 | 24 | 17 |
2. What changed across the year
Winter's founders pitched platforms; Fall's pitch jobs. The agent count stays high all year (28, 36, 37, 36), but the descriptions narrow: fewer general assistants, more agents for one named task in one named industry, which is the vertical AI pattern (149 across the year) applied inside the agent category. Infrastructure follows the energy, security ignores it, and the marketplace listings in our data (29 companies, no batch) are the control group: they skew to small, revenue first products.
3. Using the batch view
Investors read batches as vintages; founders should read them as competition maps. If your category doubled between Spring and Fall, the batch table tells you before the headlines do. Every company named here has a page with founders and story, and batch searches run free on the site.
4. Vintages, honestly read
A caveat before the comparisons harden into folklore: batch size is partly an artefact of how completely a batch has published when a database is compiled, and categories are assigned from company descriptions, not from audited filings. Read the table as a strong sketch, not a census. Within those limits the direction is consistent across too many rows to be noise: the centre of the cohort moved from platforms to jobs, from general to vertical, and the Fall intake is the most specialised of the four.
The batch pages and the company pages behind them are the working tool here: every number in this article can be re-derived from the database in a few searches, and should be, before anyone quotes it in a deck.
Source: AIToolGuide 2026 startups database (513 AI companies), compiled from Y Combinator 2026 batch listings and the TrustMRR and Indie Hackers marketplaces.