YCombinator

Y Combinator (YC) is a pioneering startup accelerator and venture capital firm founded in 2005 by Paul Graham, Jessica Livingston, Robert Morris, and Trevor Blackwell, renowned for inventing the modern accelerator model by funding large batches of early-stage startups with seed capital, intensive mentorship, and a structured three-month program culminating in Demo Day pitches to top investors. As of 2025, YC has funded over 5,000 companies with a combined portfolio valuation exceeding $600 billion, investing $500,000 in each accepted startup (on standard terms) across four annual batches while providing access to a vast alumni network, expert advice, and resources like Bookface for founder connections. The portfolio boasts dozens of unicorns and iconic successes including Airbnb, Dropbox, Stripe, Coinbase, DoorDash, Instacart, Reddit, Twitch, and Gusto, with a track record of producing far more billion-dollar companies than any other accelerator and ongoing support for alumni through programs like Work at a Startup and Series A guidance.