Cost sharing means the amount a participant or beneficiary is responsible for paying for a covered item or service under the terms of the group health plan or health insurance coverage. Cost sharing generally includes copayments, coinsurance, and amounts paid towards deductibles, but does not include amounts paid towards premiums, balance billing by out-of-network providers, or the cost of items or services that are not covered under a group health plan or health insurance coverage.
29 CFR § 2590.716-3
The definitions in this part apply to 2590.716 through 2590.722, unless otherwise specified. In addition, for purposes of 2590.716 through 2590.722, the following definitions apply: