The S.S. Maxwell brand was owned by the Targ & Dinner Music Company of Chicago and lasted from the early 1930s to the late 1940s. S.S. Maxwell instruments were made by Regal and Harmony - who built standard flat-top acoustics & ukuleles, but Kay also made S.S. Maxwell acoustic guitars with f-holes and resonator guitars.

Source: Guitar Stories: The Histories of Cool Guitars. Michael Wright. Hal Leonard Corporation, 1 Jan 2000