What is the ruling on a dentist working under a contract by which he receives a fixed 30% of the clinic's income, a fixed housing allowance, and an airline ticket, taking into account that this may lead to a loss for the polyclinic if the income is low? Is it permissible for the doctor to receive a salary for his annual leave?

For the validity of an ijarah (lease/hire contract), the ujrah (wage/rent) must be known. If it is a fixed amount, it is permissible by consensus. If it is a percentage, such as 30%, there is a dispute among scholars. The majority hold it to be impermissible due to the jahalah (uncertainty) of what the worker will receive, whereas the Hanbalis permitted it by analogy with musaqat (irrigation contract) and muzara'ah (sharecropping).

As for combining a percentage with a fixed wage, it is prohibited by most scholars. However, it is narrated from Ahmad that it is permissible, and this was the opinion of some of the early generations (Salaf). So, if the wage is 30% of the clinic's income along with housing allowance and an airline ticket, this is a combination of the two. The more cautious approach is for the salary to be a fixed amount only, or a percentage only, and not to combine them.

If the employer agrees to the agreed-upon percentage, there is no harm upon you, as he may hope for a large income, and a difference in profit is inherent in both scenarios.