15 Y Combinator companies with a founder who worked at Citadel before.
Updated weekly, last on November 9, 2026. Roster from Y Combinator's public directory.
| Company | Batch | Team | 6 mo | 12 mo | Open roles | Total raised | Last round |
|---|---|---|---|---|---|---|---|
Apollo is the foundation of your entire go-to-market strategy. | W16 | 987 | +44% | +54% | 45 | $251M | Series D$100M, Aug 2023 |
1st federally regulated exchange where people can trade on events | W19 | 604 | +17% | +83% | YC | $2.9B | Undisclosed round$30M, Jul 2026 |
We automate operations for hospitals and health systems | W15 | 271 | +7% | +19% | 13 | $203M | Series D$85M, Jan 2025 |
AI-driven learning, content, and coaching for sales teams | W19 | 88 | +1% | YC | $14.1M | Series A$11M, Jan 2021 | |
24/7 Global Stock Exchange | X25 | 12 | +50% | +50% | YC | $10M | Seed$9.5M, Mar 2026 |
Intelligent media storage for creative teams. | F25 | 8 | +33% | YC | $500K | YC investment$500K, Oct 2025 | |
Co-located trading facility and matching engine on one chip. | W25 | 7 | 0% | +17% | YC | $500K | YC investment$500K, Jul 2025 |
AI research lab automating all of investing | W24 | 7 | YC | ||||
Automating Corporate Compliance, Worldwide | X26 | 4 | 0 | $500K | YC investment$500K, Jun 2026 | ||
AI + human review to solve data cleaning - accessible via API or Excel | X25 | 4 | 0 | $500K | YC investment$500K, Jan 2026 | ||
Planet-scale people discovery. | S25 | 3 | 0 | $500K | YC investment$500K, Sep 2025 | ||
AI agents for web testing | X25 | 2 | 0 | $500K | YC investment$500K, Jul 2025 | ||
AI agents for compliance at institutional trading firms | S26 | 1 | 0 | ||||
AI-Native Medical Billing Services | W26 | 1 | 0 | $500K | YC investment$500K, Mar 2026 | ||
Safe & Secure Cash Management for Businesses | W19Acquired | 1 | 0 | SeedMar 2019 |
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
15 Y Combinator companies have a founder who worked at Citadel; 14 are active.
2 companies posted roles in the last 60 days, led by Apollo.io (45 roles) and Qventus (13 roles). 8 mark themselves as hiring on YC's directory.
By team growth over 6 months (10+ people): QFEX (+50%), Apollo.io (+44%) and Kalshi (+17%).
Largest latest rounds in the last 12 months, after their YC batch: Kalshi ($30M) and QFEX ($9.5M).