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YC companies founded by ex-Citadel people

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.

Hiring the mostlast 60 days
45 roles
Apollo.ioW16
  1. 2Qventus13
See all 2
Fastest growingteam, 6 months
+50%
QFEXX25
  1. 2Apollo.io+44%
  2. 3Kalshi+17%
See all 4
Raised the mostlast 12 months
$30M
KalshiW19
  1. 2QFEX$9.5M
See all 2
Companies
15
Active
14
Hiring, last 60 days
2
Open roles, 60 days
58
People on these teams
2,000
Showing 15 of 15 companies
CompanyBatchTeam6 mo12 moOpen rolesTotal raisedLast round
Apollo is the foundation of your entire go-to-market strategy.
W16987+44%+54%45$251MSeries D$100M, Aug 2023
1st federally regulated exchange where people can trade on events
W19604+17%+83%YC$2.9BUndisclosed round$30M, Jul 2026
We automate operations for hospitals and health systems
W15271+7%+19%13$203MSeries D$85M, Jan 2025
AI-driven learning, content, and coaching for sales teams
W1988 +1%YC$14.1MSeries A$11M, Jan 2021
24/7 Global Stock Exchange
X2512+50%+50%YC$10MSeed$9.5M, Mar 2026
Intelligent media storage for creative teams.
F258+33% YC$500KYC investment$500K, Oct 2025
Co-located trading facility and matching engine on one chip.
W2570%+17%YC$500KYC investment$500K, Jul 2025
AI research lab automating all of investing
W247  YC
Automating Corporate Compliance, Worldwide
X264  0$500KYC investment$500K, Jun 2026
AI + human review to solve data cleaning - accessible via API or Excel
X254  0$500KYC investment$500K, Jan 2026
Planet-scale people discovery.
S253  0$500KYC investment$500K, Sep 2025
AI agents for web testing
X252  0$500KYC investment$500K, Jul 2025
AI agents for compliance at institutional trading firms
S261  0
AI-Native Medical Billing Services
W261  0$500KYC investment$500K, Mar 2026
Safe & Secure Cash Management for Businesses
W19Acquired1  0SeedMar 2019

How this works

1. The roster

Every launched company in YC's public directory, with its batch, status, industry and location. New companies show up the week YC lists them.

2. The numbers

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.

3. The lists

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.

Built with Crustdata. Get your own API key and build your own.

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.

  • Company search for team size, growth and funding
  • Job search with a count by company, for who is hiring and for what
  • A watch that re-runs the search weekly and sends only what changed
# 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

Questions about ex-Citadel founded YC companies

How many ex-Citadel founded YC companies are there?

15 Y Combinator companies have a founder who worked at Citadel; 14 are active.

Which ex-Citadel founded YC companies are hiring?

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.

Which ex-Citadel founded YC companies are growing fastest?

By team growth over 6 months (10+ people): QFEX (+50%), Apollo.io (+44%) and Kalshi (+17%).

Which ex-Citadel founded YC companies raised the most?

Largest latest rounds in the last 12 months, after their YC batch: Kalshi ($30M) and QFEX ($9.5M).

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