By the beginning of the 21st century, the K-pop market had slumped and early K-pop idol groups that had seen success in the 90's were on the decline. H.O.T. disbanded in 2001, while other groups like Sechs Kies, S.E.S., Fin.K.L, Shinhwa, and g.o.d became inactive by 2005. Solo singers like BoA and Rain grew in success. However, the success of boy band TVXQ after its debut in 2003 marked the resurgence of idol groups to Korean entertainment and the growth of K-pop as part of "Hallyu". The birth of second-generation K-pop was followed with the successful debuts of SS501 (2005), Super Junior (2005), Big Bang (2006), Wonder Girls (2007), Girls' Generation (2007), Kara (2007), Shinee (2008), 2NE1 (2009), 4Minute (2009), T-ara (2009), f(x) (2009), and After School (2009).