This bill prohibits an insurer, nonprofit health service plan, or health maintenance organization (collectively known as carriers) from changing the coverage of services or benefits provided under a health insurance policy or contract during the term of the policy or contract. A carrier may change the coverage of services or benefits on renewal of the policy or contract. A carrier that provides coverage for prescription drugs (including through a pharmacy benefits manager) may not remove a drug from its formulary or move a prescription drug or device to a benefit tier that requires a higher deductible, copayment, or coinsurance during the term of the policy or contract; a carrier may do so on renewal.