What is the ruling on working for a health coverage fund that collects compulsory contributions from employees and their employers to reimburse treatment expenses or cover percentages of surgery and delivery costs according to a specific regulation, while retaining any surplus in the fund?

The fundamental difference between permissible cooperative insurance and impermissible commercial insurance lies in the ownership of the surplus. In cooperative insurance, the surplus is either returned to the policyholders or carried over to the following year as part of the fund's capital. In contrast, in commercial insurance, the surplus belongs to the insurance company, and this is prohibited because it involves consuming people's wealth unlawfully. Since the mentioned fund implements this clause, it appears that its system is cooperatively legitimate, but a definitive judgment requires reviewing all of its provisions.