Military administration?

[Trithemius]

The right side of the tree also gives access to the skill which gives a flat 10% boost to business wealth across your empire. Juicy! I'd like to know if that stacks if you buy the ability for multiple geisha.

I just promoted a second rank 6 geisha to have Entrepreneur and my overall income did not increase. I did not end-turn to see if it would recalculate, but all other effects appeared to recalculate so I am going to assume that the +10% wealth from business buildings across all provinces is not stackable.

I suppose this makes sense for the "top tier" effects: what if all your ishin shishi actions were -30% cost, combined with each characters' personal action cost discount!?