For the most part, yes. Health plans inside and outside the health insurance marketplace must provide the same basic set of benefits, and they are no longer allowed to exclude coverage of a pre-existing condition. In addition, plans both inside and outside must provide a minimum level of financial protection to their policyholders. Specifically, plans must cover at least 60 percent of what the average person would spend on covered benefits and there is a cap on the maximum amount you will pay out of pocket ($7,350 for an individual and $14,700 for a family in 2018).
There are some key differences between plans sold inside and outside the health insurance marketplace. First, you may only obtain premium tax credits and cost-sharing reductions through the health insurance marketplace. Second, plans sold through the health insurance marketplace must be certified by the marketplace as meeting minimum coverage and quality standards. Plans sold outside the marketplace may not always meet those standards particularly if the plan is grandfathered or otherwise doesn't need to comply with ACA protections (i.e., grandmothered or transitional plans). See Resources, ACA Consumer Protections for Private Coverage for more information about grandfathered and grandmothered plans. (45 C.F.R. § 147; 26 U.S.C. § 36B; 45 C.F.R. § 156.130; 81 Fed. Reg. 94058, Dec. 22, 2016).