IG Farben
After completion, the building was the headquarters of IG Farben for 15 years. IG Farben was an indispensable part of the German industrial base from its establishment in 1925, and the world's largest chemical and pharmaceutical company. Although IG Farben had been reviled on the far right and accused of being an "international capitalist Jewish company", the company nonetheless remained a large government contractor under Nazi Party rule.