The largest insurers in the Health Insurance Marketplace raised premiums an average 75% more this year than smaller insurers in the same state, according to a new study in the Harvard Journal of Technology Science. The largest insurance issuers raised rates by an average 23.9%, while the other issuers raised rates by an average 13.7%, the study found. Moreover, the largest insurers did not appear to be paying for higher medical costs per premium dollar. The authors called the findings “especially relevant” in light of recent market consolidation attempts by large issuers. “This paper provides evidence that…the largest on-exchange insurers may be in a better position to practice anti-competitive pricing compared to their same-state counterparts,” they said. The study examined changes in health insurance premiums by individual health insurance issuers in 34 federally facilitated and state partnership Health Insurance Marketplaces.