What is the ruling on subscribing to the savings fund (pension scheme) in which 4% of the employee's salary is deducted and the company adds 6%, and an insurance company invests the amount, with the option not to take interest, knowing that participation is optional for me and compulsory for others, and that non-participation significantly reduces the final bonus, while participation increases it fourfold?

The commercial insurance system offered by the company is impermissible to subscribe to except under compulsion. In such a case, the subscriber is permitted to benefit from the amount he has paid, and only from what his company has paid for him. Assuming the company invests the funds in a Sharia (definition)-compliant manner, the subscriber is permitted to benefit from the profit generated by what both he and his company have paid.