100 Mark Die Frankfurter Bank

Die Frankfurter Bank was one of a handful of German private issuing banks still operating under the transitional framework that followed unification in 1871. The Reichsbank had been established in 1876 specifically to consolidate and eventually eliminate these regional note-issuing privileges, and by 1890 the pressure on private issuers was already acute. Frankfurt's bank held on longer than most, but its circulation rights were formally extinguished in 1901.

The guilloche underprint was the era's primary mechanical deterrent against lithographic counterfeiting — engine-turned lathe work that was genuinely difficult to reproduce by hand.