Karl Theodor Helfferich (22 July 1872 – 23 April 1924) was a German politician, economist, and financier from Neustadt an der Weinstraße in the Palatinate.

He soon became a leader in the German government's policy of economic imperialism, and in 1906 he was appointed director of the Anatolian Railway which was financed by Deutsche Bank.

During the November Revolution, Helfferich became an early supporter of the self proclaimed "national socialist" Eduard Stadtler and helped fund the founding of his Anti-Bolshevist League on December 1, 1918, receiving a cash donation of 5,000 marks from Paul Mankiewitz, the director of Deutsche Bank.

Stadtler, the founder and leader of the Anti-Bolshevist League, according to his own account, arranged for the murder of Rosa Luxemburg and Karl Liebknecht on January 12, 1919, and broke "Gustav Noske's hesitance" about using the military in Berlin days before.

Elected to the Reichstag of 1920, Helfferich led the conservative and monarchist right, known as the Deutsch-Nationalen, and strongly opposed reparations and the economic fulfillment of the Versailles Treaty.

[4] After weeks of deliberation and statements, the presiding judge ruled in favor of Erzberger, forcing Helfferich to pay a fine of 300 marks.

In the eyes of the public, support had fully rallied behind Helfferich, mirroring the sway of the political climate during this tumultuous period.