How is Enterprise Calculated?

My CEO, Teddy Bears Picnic on LU has recently started to be charged enterprise tax.

Only 2-3B so far, but I am only at 298 corporations.

I was wondering if there is any documentation or explanation about how this tax is calculated please?

I remember reading something about how a CEO becomes less profitable as it becomes larger, over 400 corps i believe?

Another post mentioned that profit transfer can affect the tax, has anyone seen this?

My last question is about Enterprise score. Does having a higher profit share percentage mean you have a higher score, or is this not a factor?

Thanks for having a look guys

Ted