I.O.I (Korean: 아이오아이, also known as IOI) is a South Korean girl group under YMC Entertainment and CJ E&M. The members consist of Somi, Sejeong, Yoojung, Chungha, Sohye, Zhou, Chaeyeon, Doyeon, Mina, Nayoung, Yunjung. They made their official debut on May 4, 2016 with their debut mini album 'Chrysalis" and held their debut stage on Mnet's M! Countdown on May 5, 2016. http://www.nowkpop.com/2016/04/02/i-o-i-profile/