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 his own. After the Johnson bout, Klitschko's camp began negotiations for a potential fight with former WBA Champion Nikolai Valuev, but the match failed to materialize due to economic disagreements. On 29 May 2010, Vitali Klitschko defeated Polish heavyweight contender Albert Sosnowski by KO at 2:30 in round 10 of 12. Sosnowski was knocked down by a right hand in the 10th round, prompting referee Jay Nady to immediately wave off the fight. The fight took place at Veltins-Arena, Gelsenkirchen, Nordrhein-Westfalen, Germany. Vitali Klitschko weighed in at 112 kg (247 lbs), while Sosnowski weighed in at 110 kg (242.5 lbs).