This is actually a rather common sign. Many people may not recall it, but the "fish decals" which Christians put on their automobiles first began to appear in the late 1970s, and at that time "Ichthus" (i'm not going to bother to change the keyboard setting in order to do the Greek) would appear in Greek letters inside the stylized fish symbol. The point is that it refers to Matthew Chapter 4, verse 19: (in the King James Version)
And he saith unto them, Follow me, and I will make you fishers of men.
The symbology was obscure and uncommon, but not unknown in Christian art and literary illustration. It has proliferated widely since the creation of the automobile decal.
Although the original post describes something slightly different--placing
eta where
chi appears in "ichthus," i strongly suspect that this is what the author refers to, and the company to for which she works has a Christian origin--one of the founders or a benefactor of the company.
Those who are called, or who call themselves, secular humanists have parodied this symbol with their "walking fish" symbol: