In the late 19th century Bofors steel works, which initially supplied forgings and castings to the factory, started to expand into the weapons business.

With Alfred Nobel's help, by the 1911 AB Bofors-Gullspång had outcompeted, bought and closed down its competitor.

When in 1913 a turbine plant STAL was founded in the town, both good metalwork facilities and skilled labor were available.

Today the two main industrial areas are those of Siemens Energy turbines and metal processing.

Administratively Finspång remained part of the rural municipality Risinge until 1942, when it was made a market town (köping).