Paying a Premium on Your Premium? Consolidation in the U.S. Health Insurance Industry

We are grateful for helpful comments by Michael Chernew, Julie Cullen, Roger Feldman, Chris Snyder, Alan Sorensen, seminar participants at American University, Brown University, Dartmouth College, the Department of Justice, Harvard University, Ohio State University, UCLA, University of Rochester, University of Michigan, Wharton, and participants at the American Economic Association Annual Meetings, the International Industrial Organization Conference, the American Society of Health Economists Conference, the 20th Annual Health Economics Conference, the University of British Columbia Summer Industrial Organization Conference, the Searle Center Symposium on Antitrust Economics and Policy, the NBER Summer Institute, the "New Perspectives on Health and Health Care Policy" conference at the Federal Reserve Bank of Chicago and the HEC Montreal Conference on the Industrial Organization of Healthcare. We thank Michael Chernew, Jose Guardado, Woolton Lee, and Dennis Scanlon for valuable discussions on key data sources. Dafny gratefully acknowledges funding from The Searle Center on Law, Regulation, and Economic Growth at the Northwestern University School of Law. The views expressed herein are those of the author(s) and do not necessarily reflect the views of the National Bureau of Economic Research.

• October 20, 2009