in group meetings. Founders also participate in weekly meetups where guests from the Silicon Valley ecosystem (successful entrepreneurs, venture capitalists, etc.) speak to the founders. Y Combinator's motto is "Make Something People Want." The program teaches founders how to market their product, refine their teams and business models, achieve product/market fit, and scale the startup into a high growth business, etc. The program ends with Demo Day, where startups present their business and technology prototypes to potential investors. Y Combinator operates additional programs and a fund designed to support and invest in startups which have already graduated from the main accelerator program. The Series A Program, YC Post-A Program, YC Growth Program, and YC Continuity fund are operated by the same team and focus on helping fast growing YC startups, and startups raising their Series B funding of $20 million to $100 million. Y Combinator has introduced additional programs since 2015, including: In July 2015, Y Combinator introduced the YC Fellowship Program aimed at companies at an earlier stage than the main program. In October 2015, Y Combinator introduced the YC Continuity Fund. The fund allows Y Combinator to make pro rata investments in their alumni companies with valuations under $300 million. Y Combinator will also consider leading or participating in later stage growth financing rounds for YC companies. Nonprofit research lab YC Research was announced in October 2015. Researchers are paid as full-time employees and can receive equity in Y Combinator. OpenAI was the first project undertaken by YC Research, and in January 2016 a second study on basic income was also announced. Another project is research on new cities. Australian quantum physicist Michael Nielsen is a research fellow at YC Research since 2017. In October 2015, YC introduced YC Research to fund long-term fundamental research. YC President Sam Altman donated $10m. During 2017–2019, YC launched Startup School, the Series A program, the YC Growth program, Work at a Startup, and YC China. In March 2019, it was reported that Y Combinator was moving headquarters to San Francisco. As of late 2021, Y Combinator had invested in >3,000 companies, most of which are for-profit. Non-profit organizations can also participate in the main YC program. Few non-profits have been accepted in the last years, among them Watsi, Women Who Code, New Story, SIRUM, Zidisha, 80,000 Hours, and Our World in Data. People Y Combinator was founded in March 2005 by