A startup or start-up is a company or project undertaken by an entrepreneur to seek, develop, and validate a scalable economic model.[1][2] While entrepreneurship refers to all new businesses, including self-employment and businesses that never intend to become registered, startups refer to new businesses that intend to grow large beyond the solo founder.[3] At the beginning, startups face high uncertainty[4] and have high rates of failure, but a minority of them do go on to be successful and influential.[5] Some startups become unicorns; that is privately held startup companies valued at over US$1 billion.