"[N]ational firms such as Aetna, United, and CIGNA are far better positioned to serve national employers and other large, self-insured groups than to compete for individual households.... The vast majority of purchasers on the ACA Marketplace are low-to-moderate income households, who are searching for low-priced health plans.... As a result, the Blue Cross Blue Shield and other regional plans generally ... enjoy a cost and premium advantage over national plans and tend to dominate their Marketplaces."  MORE >>