The cool thing is that it's not very well defined! I feel like these are interesting distinctions that each need a term:

• large business owners/shareholders/executives with close political connections/influence
• small/medium business owners/investors with extravagant wealth, some state or regional political connections.
• small business owners
• working small business owners with a handful of employees
• working small business owners with no employees
• professionals
• independent professionals
• independent professionals with employees
• managers

I've heard "petit-bourgeois" used to refer to more than one of these (some of them I just threw in there myself)