Health insurers incurred an average underwriting loss of 4.2% in the individual market in 2014, the first year they participated in the Affordable Care Act marketplaces, according to a study released today by the Commonwealth Fund. Medical claims averaged 5.7% higher than projected, but were only 2.4% higher after reinsurance credits. The transitional reinsurance program, funded by health insurance issuers and certain self-insured group health plans, was established by the ACA to stabilize premiums in the individual market for the first three years of the new marketplaces. The study looked at 144 insurers with at least 1,000 individual-market enrollees that were active in 2013 and sold primarily ACA-compliant policies in 2014. Financial performance varied from an average 8.5% profit in the top quartile of insurers to an average 21.8% loss in the bottom quartile of insurers.