My father was an aeronautical engineer, and his father was a doctor. They both obviously had high IQs, and I assume my father is also high IQ enough to be a doctor, if he had wanted to be.
I'm not as high IQ as my father, and I'm also higher time preference, so there is no way I could ever be a doctor or an aeronautical engineer.

What is the minimum IQ of a businessman or entrepreneur, especially someone involved in finance?

I'll use the wikipedia description of a businessman "The term "businessperson" may refer to a founder, owner, or majority shareholder of a commercial enterprise; or it can characterize a high-level executive who does the everyday running and management of a company even if that executive is not the owner".