EBSA annually produces auxiliary data focused on characteristics of employer-sponsored insurance. This data, when linked to the March Annual Social and Economic Supplement to the Current Population Survey (March CPS), generates estimates of the number of individuals with different types of insurance coverage. Additionally, this data can be used to produce statistics on various aspects of employer-sponsored insurance, such as: sector sponsoring coverage; funding source; type of health plan; and value. The data in the auxiliary file is primarily imputed from other datasets including the Medical Expenditure Panel Survey Household Component (MEPS-HC), Medical Expenditure Panel Survey Insurance Component (MEPS-IC), the Kaiser/HRET Survey of Employer- Sponsored Insurance and the National Compensation Survey (NCS). The Health Insurance Coverage Bulletin provides highlights of the year's data as well as summary tables. The Technical Appendix details the imputation methodology used to produce the data. The Layout of the March CPS Auxiliary Data provides the layout of the fixed format data files as well as a brief description of each variable. The raw data is provided in both Stata and SAS versions.