The 18 YC W21 companies whose latest reported round, after their YC batch and in the last 12 months, was the largest.
Updated weekly, last on November 9, 2026. Roster from Y Combinator's public directory.
| # | Company | Team | 6 mo | 12 mo | Open roles | Total raised | Last round |
|---|---|---|---|---|---|---|---|
| 1 | Seamless mobility to, through, and from space. It starts with 100%… | 451 | +17% | +33% | 4 | $2.4B | Series E$1B, Sep 2026 |
| 2 | Telehealth dietitians covered by insurance | 4,256 | 7 | $213M | Series C$100M, May 2026 | ||
| 3 | Get up and running with large language models. | 77 | +38% | +64% | 0 | $80.1M | Series B$65M, Jul 2026 |
| 4 | The data layer for physical AI | 231 | +31% | +75% | 3 | $110M | Series C$60M, Feb 2026 |
| 5 | Protecting the grid today, preparing the grid for tomorrow | 221 | +18% | +51% | 1 | $97.2M | Series B$55M, Nov 2025 |
| 6 | Voice AI for developers. | 150 | +50% | +114% | 4 | $70.6M | Series B$50M, May 2026 |
| 7 | Modernizing commercial insurance | 107 | +11% | +43% | 17 | $61.6M | Series B$42M, Mar 2026 |
| 8 | all-in-one operating system (OS) for telcos | 121 | +34% | +51% | 8 | $66.3M | Series B$40M, Mar 2026 |
| 9 | Internet for the urban developing world. | 382 | +18% | +41% | 0 | $75.6M | Series B$40M, Mar 2026 |
| 10 | A digital wallet for the Middle East & North Africa | 324 | +15% | +45% | 5 | $30.5M | Series A$22M, May 2026 |
| 11 | AI Agents for Oncology EHRs | 98 | +48% | +72% | 3 | $37.1M | Series B$22M, May 2026 |
| 12 | Shift FinOps Left: Proactively Find & Fix Cloud Cost Issues | 29 | +16% | YC | $21.9M | Series A$18.8M, Nov 2025 | |
| 13 | Recover from any outage in 10 minutes or less. | 51 | +46% | +65% | 0 | $26.2M | Series A$15.9M, Jun 2026 |
| 14 | AI-powered Compliance Platform for PCI 4, CCPA, HIPAA, CIPA, 50+ laws | 51 | −4% | +38% | 0 | $25.8M | Series A$14M, Nov 2025 |
| 15 | User research on autopilot. | 59 | −6% | −11% | 4 | $15.5M | Series A$13M, Nov 2025 |
| 16 | Tech-enabled fulfillment provider in the Middle East & Africa | 190 | 0 | $15.9M | Series A$12.6M, Feb 2026 | ||
| 17 | Source better parts by partnering directly with vetted manufacturers | 122 | +8% | +30% | 1 | $16.1M | Series A$12.1M, Nov 2025 |
| 18 | The AI Underwriting OS for Commercial, Specialty & E&S insurance | 167 | +7% | +37% | 0 | $7.7M | Series A$7M, Nov 2025 |
Every launched company in YC's public directory, with its batch, status, industry and location. New companies show up the week YC lists them.
Each company is matched to Crustdata by its website. Crustdata adds team size and its change over 6 and 12 months, open roles from job postings, reported funding, and founders' past employers.
Hiring the most counts distinct roles posted in the last 60 days. Growth needs 10+ people today, shrinking 20+ a year ago, so tiny teams do not top the lists. Rebuilt every week.
The numbers on this page come from three Crustdata API calls. Crustdata tags 5,000+ companies with Y Combinator as an investor; swap the filter for any investor, industry or headcount range and track your own list, with founders' work emails one call away.
# 1. every company with Y Combinator as an investor curl https://api.crustdata.com/company/search \ -H "authorization: Bearer $CRUSTDATA_API_KEY" \ -H "x-api-version: 2025-11-01" \ -d '{ "filters": { "field": "funding.investors", "type": "in", "value": ["Y Combinator"] }, "fields": ["basic_info.name", "headcount.total", "headcount.growth_percent", "funding.total_investment_usd"], "limit": 100 }' # 2. open listings per company, last 60 days (limit 0 = counts only) curl https://api.crustdata.com/job/search \ -H "authorization: Bearer $CRUSTDATA_API_KEY" \ -H "x-api-version: 2025-11-01" \ -d '{ "filters": { "op": "and", "conditions": [ { "field": "company.basic_info.company_id", "type": "in", "value": [...] }, { "field": "metadata.date_added", "type": "=>", "value": "2026-08-24" } ]}, "limit": 0, "aggregations": [{ "type": "group_by", "field": "company.basic_info.company_id", "agg": "count" }] }' # 3. the same company filter as a weekly watch: POST /watch/company/search
334 companies were in Y Combinator's Winter 2021 batch (W21); 226 are active.
46 companies posted roles in the last 60 days, led by REGENT (30 roles), Shepherd (17 roles) and Codingal (9 roles). 77 mark themselves as hiring on YC's directory.
By team growth over 6 months (10+ people): OpenCode (+200%), Venu AI (+58%) and Vapi (+50%).
Largest latest rounds in the last 12 months, after their YC batch: Stoke Space ($1B), Nourish ($100M) and Ollama ($65M).