Friedrich Wilhelm "Fritz" von Frantzius[1] (1865-1917) was a German-born American banker, broker and bookkeeper.

He worked as a bookkeeper for Lipps & Button Silk Mills from 1888 to 1889, for Matthiessen & Hegeler Zinc Co. from 1889 to 1892, for Siemens & Halske Electric Co. from 1892 to 1893 and for J. F. Wollen-sac from 1893 to 1896.

He then worked in the real estate business with S. E. Gross and Sam Brown Jr. from 1896 until he became a banker and broker in 1899 at the firm Von Frantzius & Krusemarck.

In 1901 he began working with Ben Marcuse at the firm Von Frantzius & Co.[4] On December 9, 1900, in Berlin, von Frantzius was selected as the Councilor of the Foreign Office and Councilor of the High Court for the International Court of Arbitration at The Hague.

[4] On June 23, 1913, von Frantzius married his second wife, the Australian dancer Saharet, with whom he had long been obsessed.