Yup, pretty sure they self-insure. Some big car rental companies also self-insure, because they are at the scale where they already have their own repair shops,

Yup, pretty sure they self-insure. Some big car rental companies also self-insure, because they are at the scale where they already have their own repair shops, and the premiums would be more expensive than just paying out the damages themselves (edit: and then they can sell their own insurance to renters!)