Y Combinator is an American seed accelerator, started in March 2005. Twice a year they invest a small amount of money in a large number of startups. Y Combinator provides seed money, advice, and connections to startups in exchange for 7% equity. It is regarded as the best seed-stage accelerator in the world by its founders as well as the most commercially successful.It was founded by Trevor Blackwell, Paul Graham, Jessica Livingston, Robert Tappan Morris.
In 2014, Sam Altman was named president of Y Combinator. In 2014 Altman blogged that the total valuation of all Y Combinator companies had surpassed $30 billion, including well-known companies like Airbnb, Dropbox, Zenefits and Stripe
