Manufacturers' list prices for insulin have increased dramatically since the early 2010s in the United States. In this report, we present results from a comparison of U.S. and international prices for insulins using a price index approach. We describe the shares of volume and sales for all insulins and different categories of insulin in the United States and 33 comparison Organisation for Economic Co-operation and Development countries. For the market basket of insulins sold in both the United States and comparison countries, we report ratios of U.S. insulin gross prices (that is, prices prior to the application of rebates paid by drug companies to buyers) to those in other countries. This report updates a prior RAND Corporation report: Andrew W. Mulcahy, Daniel Schwam, and Nathaniel Edenfield, Comparing Insulin Prices in the United States to Other Countries: Results from a Price Index Analysis, RAND Corporation, RR-A788-1, 2020. In the current report, we use more-recent data and include new supplementary analyses, editorial changes, and updates to reflect the evolving insulin market landscape. This research was funded by the U.S. Department of Health and Human Services Office of the Assistant Secretary for Planning and Evaluation under Contract No. HHSP233201500038I and carried out within the Payment, Cost, and Coverage Program in RAND Health Care.RAND Health Care, a division of the RAND Corporation, promotes healthier societies by improving health care systems in the United States and other countries. We do this by providing health care decisionmakers, practitioners, and consumers with actionable, rigorous, objective evidence to support their most complex decisions. For more information, see www.rand.org/health-care, or contact