In FAQ Part X on the Affordable Care Act, the Department of Labor (the "DOL") says that, if one of the benefit packages in a group health plan is a Medicare Advantage plan, the employer is not required to provide a summary of benefits and coverage (an "SBC") for that package.
The general rule is that a group health plan must provide a separate SBC for each benefit package it offers. But that rule does not apply to a benefits package which is a Medicare Advantage plan. The FAQ explains that Medicare Advantage benefits are Medicare benefits (financed by the Medicare Trust fund and equivalent to Medicare A and B benefits, which are set by Congress and regulated by the Centers for Medicare & Medicaid Services (CMS)). They are, therefore, not health insurance coverage and Medicare Advantage organizations are not required to provide an SBC with respect to such benefits.