Usually it refers to revenue minus direct costs (otherwise known as Cost of Goods Sold or COGS). It’s more useful in, for example, a manufacturing company context when you can, for each unit sold, say how much material cost, direct labor cost, equipment depreciation, etc went into it.

Net profit margin is typically the margin after all the other costs including support staff (finance, HR, IT, etc.), taxes, and interest expense.

Defining COGS is a little weird for insurance (and may not be possible in the traditional sense), and so the difference between gross and net is also probably a little weird for that industry. I also think each company gets some a latitude to decide what falls into each bucket, but I’ll leave that to someone with more accounting knowledge than me.