According to the World Boxing Organization’s Regulations of World Championship Contests Section 5 Defense of Title,

“SECTION 5 DEFENSE OF THE TITLE:

(a) Each WBO World Champion except in the Heavyweight Division shall defend his title at intervals not greater than nine (9) months counting from the date of the acquisition thereof or from the last compulsory defense …

(c) The WBO World Championship Committee may, in its discretion, vacate a Champion’s title regardless of cause or fault if the Champion fails to defend his title within a nine (9) month period (12 months in the case of the Heavyweight Division)… complied with the WBO and ABC rating criteria.”… Read more 15MAR13_Zauerbek_Baysangurov