Oberstgruppenführer was the highest commissioned SS rank with the exception of Reichsführer-SS, which was a special rank held by Heinrich Himmler. Translated as “Colonel Group Leader” an Oberstgruppenführer was considered the equivalent of a Colonel General (Generaloberst).
First created in 1942, Oberstgruppenführer was only held by four people during the three years of its existence. The following individuals held this highest of SS ranks.
(und Generaloberst der Polizei)
(und Panzer-Generaloberst der Waffen-SS)
(und Generaloberst der Waffen-SS)
In 1944, Heinrich Himmler offered to appoint Albert Speer to the honorary rank of Oberstgruppenführer, however Speer would claim in later years he turned Himmler down due his distaste for the SS. Hermann Göring was also offered the rank in 1945, but refused to accept the position due to his dislike for Himmler.
Those obtaining the rank of Oberstgruppenführer were also typically granted equivalent police or Waffen-SS General rank. Franz Xaver Schwarz, who held Ehrenführer (honorary) rank, was the only holder of the rank who was not granted equivalent police or Waffen-SS rank.
The rank Oberstgruppenführer has also appeared in fiction, and was depicted in the novel Fatherland, set in the 1960s in a parallel history where Germany had won the Second World War. In the novel, Artur Nebe makes an appearance as an SS-Oberstgruppenführer while serving as commander of the Kriminalpolizei.