The first trademark of the newly-founded company was round in character. This was probably only because Julius Gottfried Anschütz strongly stylised the "G" of his second Christian name, almost making a "C" out of it, and then interweaved it with his other two initials "J", a stylised "I", and an oversized "A". This signet soon led to the Germania weapons factory in Zella-Mehlis mostly being referred to concisely as "IGA". And Dieter Anschütz often relates that his schoolmates and childhood friends in Zella-Mehlis often just called out "IG" to him.
The selection of a circular company logo also probably had a practical background. Because every firearm needs to have a manufacturer's stamp, this clear and distinct shape lends itself to being effectively applied even to the smallest of stamping punches. You can still clearly see this punch mark on many old firearms even today.