All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The contract between insurance companies and hospitals or healthcare institutions is, in itself, based on a valid transaction, such as the sale of medicine, hiring of doctors, and similar services.
Accordingly, the money that these hospitals and institutions receive from insurance companies is permissible.
Allah knows best.