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 Klitschko was unbeaten and a rising star in the heavyweight division, having won all 27 of his contests by knockout. On 1 April, Klitschko had a third title defense against the American Chris Byrd, who was a late replacement. Byrd made himself a difficult target and tried to thwart Klitschko's offense by being elusive. Klitschko won most of the rounds and was heading towards a comprehensive points victory when he suffered a serious shoulder injury. After the ninth round, Klitschko notified his corner that he had a shoulder pain and threw in the towel, thus handing Klitschko his first defeat