Officine Meccaniche. Italy.
Founded in 1899 in Milan (as a result of the fusion of “Grondona Comi & C” and “Miani Silvestri & C”), OM (its full name was “Societa Anonima Officine Meccaniche”) made various railway materials amongst other heavy engineering products. In 1918 OM took over the Zust car company and thus obtained a car factory at Brescia in Northern Italy.
In 1933 the car production facilities were absorbed into the Fiat group. OM became dedicated to producing commercial vehicles (as part of the Fiat group) until it was absorbed into IVECO in 1975.
(text source and more info at: Cars From Italy)
The Type 665 (shown below) greatly contributed to Officine Meccaniche’s reputation. They had their hour of glory in the 1927 Mille Miglia, where they took the first three places.