[영문]We examine differential declines in private insurance by income and age. We show that older, higher-income people in working families are more likely to retain private coverage as premiums rise, and we project these effects on future coverage rates. The analysis suggests that trends are leading to the qqqquot;grayingqqqquot; of the employment-based health insurance system, where older, higher-income people get private health insurance, and others increasingly have public coverage or go without. These changes raise questions about the private health care system’s ability to pool health risks. Population aging could interact with rising premiums and place additional pressure on an already strained employment-based health insurance system.