Is it very costly for small companies to provide insurance for their employees? we get no health insurance?

I work for a investment company but I work for one of their branches and we have no type of insurance of any type. why?
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It's based on average age and health. If the average age is 40, and there are some health issues, it could EASILY be $500 per employee, per month. If the employee wants to cover their whole family, that runs $1,000 a month per family, sometimes more.
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