Data on the operations of large U.S. corporations are available from a variety of sources. However, there is only one source of disaggregate data on the profits of corporations by industry the FTC's Line of Business Program. The FTC collected data on the domestic operations of large corporations in each of 261 4-digit FTC manufacturing industry categories. Information on a total of 588 different corporations was collected for the years 1974-1977; because of late additions, deletions, acquisitions, and mergers, the number of corporations reporting in any one year ranged from 432 to 471. The average corporation reported on about 8 business-units.