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
Wladimir Klitschko I'm ready. What're you waiting for?" Haye's trainer, Adam Booth, indicated that Haye would be willing to accept the challenge. Both sides began negotiations for a potential fight and the bout was targeted for September. As the negotiations continued to move forward, the unification fight between Klitschko and Haye was expected to take place in Germany rather than England. The IBF set a deadline to end negotiations on 17 May. A few days before the deadline to make the unification bout, Haye said he was interested in fighting the older Klitschko, Vitali, rather than Wladimir. The fight did not materialize