# Founder and alumni networks

> Map the founders, investors and alumni behind a group of companies, like the PayPal Mafia or Y Combinator, with every tie dated and sourced.

Source: https://netgraf.isik.co/uses/founder-networks
Updated: 2026-09-24

A founder network maps the people behind a set of companies: who founded what with whom, who invested, and who left to start the next one. It shows why a handful of alumni groups, like the PayPal Mafia, turn up behind so many later companies.

## Why these networks matter

Startups are built on repeated ties. People who worked together once hire, fund and co-found with each other again, and a single company's alumni can seed an industry. A map makes those repeat ties visible, along with the [brokers](https://netgraf.isik.co/learn/brokers-and-bridges) who connect otherwise separate groups of founders and investors.

## How to map one

1. Start with the origin company as an organisation node and its early team as people.
2. For each person, add the companies they founded or funded next, with business ties labelled "co-founded", "invested in" or "early employee at".
3. Date every tie. The timeline will show the diaspora spreading out.
4. Cite a source for every tie: public profiles, press, or filings.

An [ego network](https://netgraf.isik.co/learn/ego-network) is a good way to start: map one founder's ties first, then merge in the next founder's.

## Questions

### What is the PayPal Mafia?

The PayPal Mafia is the group of early PayPal employees and founders who went on to found or fund companies including Tesla, SpaceX, LinkedIn, YouTube, Yelp and Palantir. The example map below traces those ties with sources.

## Example maps

- https://netgraf.isik.co/m/paypal-mafia
- https://netgraf.isik.co/m/y-combinator
- https://netgraf.isik.co/m/openai-anthropic