The HMO format of insurance is not uncommon, but Kaiser does have a somewhat unique implementation of it. Most HMO insurances contract with healthcare providers (network) and you are only allowed to go to them. Kaiser is not the healthcare provider but it is a consortium with the medical groups, hospitals, and insurance, such that they appear as one big entity. This can create conflicts of interest, but it also creates some huge efficiencies. Everyone from GPs to specialists to pharmacy is all in the same system, so there are not issues with communication between different companies and hospitals. The also have more incentive than most insurance companies to keep you healthy to prevent you from using the more expensive types of care. In my experience, for the same premiums, KP tends to have the lowest out of pocket max and no/low deductibles compared to PPOs like Cigna or Blue Cross/Shield.