The number of different base marks Bay used are very large. In the earlest years incised marks were used in many different styles. Moulded debossed marks began to be used in the early 50s. Embossed marks were introduced ca. 1959 and after this year Bay only used embossed base marks.

The base mark "GERMANY" began to be used in the 30s and forms with this mark was used as long as ca. 1961. W. GERMANY and WEST GERMANY were introduced ca. 1959. "BAY" was introduced in the base marks ca. 1962 and was used until the reunion of Germany 1989.

Ceramics with the base mark "GERMANY" was used after the reunion of Germany 1989.