Its growth was slowed by its failure to gain recognition by employers in large plants in heavy industry until World War I.

After government control collapsed in November 1918, most leaders had to leave their posts as a result of having supported the war.

[4] Once order was restored, the DMV, which was part of the Allgemeiner Deutscher Gewerkschaftsbund (ADGB), a confederation of socialist unions,[5] attained recognition from employers and its membership spiked to 1.6 million in 1919, briefly making it the single largest union in the world.

[6] It was, however, unable to attract younger workers throughout the Weimar years and its membership sank to under a million by 1928.

[10] After World War II, in 1949, IG Metall was established as the new German federation for metalworkers.