During World War Two, the Swiss had adopted Adolf Furrer's toggle-locked MP41 submachine gun, and they found it too fragile, complex, and expensive. Looking for an alternative, one easy choice was the Finnish Suomi. Used and appreciated by the Finns, Danes, and Swedes it was reliable and available. It was adopted into service in the fastest set of trials in Swiss military history, and a batch was purchased from Tikkakoski along with a license to produce them at Hispano-Suiza in Geneva.

The initial Finnish-made guns were designated MP43, and the Swiss-made ones were the MP43/44. A total of 5200 MP43s were imported and MP43/44 production resulted in another 22,468 made between 1944 and 1951. The Swiss-made guns have a few distinctive features including an aluminum buttplate, two-position notch sights (100m/200m), and after the first few thousand, a bayonet lug to fit the standard Swiss K31 bayonet.