Klitschko brothers 5 months & 13 days. Vitali retained the WBC Heavyweight Championship until 15 December 2013, relinquishing his belt in pursuit of his political aspirations in his native Ukraine. The Klitschko brothers jointly run the professional boxing promotion companies ""K2 Promotions"" and ""K2 East Promotions"", as well as the ""Klitschko Brothers Fund"", a charity organization. They appear together on German TV shows and commercials, have a website shared between them, and support each other's training and fights. After Vitali's retirement, Wladimir continued to reign as champion & successfully defend all remaining title belts except for the WBC belt. He eventually lost
Vitali Klitschko leader. In the 2015 Kiev Mayoral election Klitschko was reelected with 66.5% of vote. For this he needed a second round of Mayoral elections between him and Boryslav Bereza after incumbent Klitschko scored 40.5% of the vote and Bereza 8.8% in the first round. (Bereza gained 33.51% of the vote in the second round of Mayoral elections.) Klitschko resigned as Petro Poroshenko Bloc chairman (on 26 May) after a new law barring a head of administration to be chairman or a member of a political party took effect on 1 May 2016. Klitschko is in favor of the Association Agreement