Apart from Marciano, only a few boxers have retired as undefeated world champions throughout history. , Joe Calzaghe, Georgi Kandelaki, Michael Loewe, Floyd Mayweather Jr., Sven Ottke, Harry Simon, Pichit Sitbangprachan, Edwin Valero, Andre Ward, retired with perfect records, without defeats or draws. Yet most of those fighters had asterisks next to their unbeaten records. Simon temporarily halted his career during a prison sentence. Valero allegedly committed suicide while still an active champion. Ottke won countless dubious decisions spending all of his career within Germany, Loewe and Kandelaki ended their careers due to injuries. Only the records of Calzaghe and Mayweather have been able to escape much controversy, with the latter retiring at 50–0. As of 2018, this has been surpassed by Thai boxer Chayaphol Moonsri, who at 33 years of age (as of May 2019) fights at mini-flyweight and is currently 53–0.