¹ In this analysis I have omitted the Miscellaneous Manufacturers and the Ordnance group. The latter was listed as a manufacturing category in the pre-war Census data but was not given in the post-war Census information.

² See footnote 21.

³ See note on Table 1. Another reason for the increase in the product value produced by the top twelve in the first decade of the century was that the share contributed by illuminating gas dropped rapidly as the century progressed.

⁴ It is, of course, possible for a company to be vertically integrated and still be in one four-digit industry. This was true of the petroleum companies, some food companies, and even primary metals and some machinery firms. The census and concentration-ratio data do not include information on mining and other extractive industries and transportation which are so important in the integrating process. On the other hand, it is quite unlikely that vertical integration would bring a company into more than four four-digit industries. A firm is more likely to move into a total of three or four four-digit industries when it develops a “full line” of products. For example, most steel companies would be in 3312 (blast furnaces and steel mills) and 3313 (electrometallurgical products) or petroleum companies would be in 2911 (petroleum refining) and 2992 (lubricating oils and grease). Production in five or more four-digit industries would certainly in most cases mean that the firm would be moving beyond a full line and providing products for quite different markets. Often these would be markets in other and different industrial groups.

⁵ I will not consider in this paper the reasons for the coming of the merger movement as my views on this important subject are summarized in “The Large Industrial Corporation and the Making of the Modern American Economy,” Stephen Ambrose, E., editor, Institutions in Modern America (Baltimore, 1968), 76–82Google Scholar and in “The Role of Business in the United States, a Historical Survey,” Daedalus, 98 (Winter 1969), 23–40.

⁶ Thorelli, Hans, Federal Anti-Trust Policy (Baltimore, 1964), 294–303Google Scholar; Livermore, Shaw, “The Success of Industrial Mergers,” Quarterly Journal of Economics, 50 (November 1935), 68–96CrossRefGoogle Scholar; Nelson, Ralph L., Merger Movements in American History, 1895–1956 (Princeton, 1959), 42–46.Google Scholar

⁷ Livermore lists 156 mergers, but ten of them cannot be considered manufacturing firms. He has four categories but two of them — the “limping” and the “marginal” groups — have been combined here into one, “partial successes.” Livermore lists no mergers in apparel, and only two or three in lumber, furniture, and printing and publishing. Petroleum shows one success (Pure Oil) and three failures, all of which were asphalt companies. In rubber the score was two failures, one success, and one partial success.

⁸ Thorp, Willard, The Integration of Industrial Operations (Washington, 1924), 236.Google Scholar Tables showing extent of integration are on page 238.

⁹ The industry groups used in the 1919 Census were different from those defined in the 1957 Standard Industrial Classification Manual.

¹⁰ While Thorp found many cases of integration in the lumber industry, all but nine of ninety-nine cases involved two simple sawing and planing processes which were not considered to be complex operations. Thorp did not consider distribution facilities in his statistics, which partially explains why he found so little vertical integration in food and liquor industries.

¹¹ Thorp, Integration of Industrial Operations, 126.

¹² Averitt, Robert T., The Dual Economy (New York, 1968), 38–44.Google Scholar

¹³ Gort, Michael, Diversification and Integration in American Industry (Princeton, 1962), 79–80.Google Scholar

¹⁴ Given in Economic Concentration, Hearings before the Subcommittee on Anti-Trust and Monopoly of the Committee of the Judiciary, United States Senate, 89th Congress, 1 Sess., Part III (Washington, 1965), 1273–1274. A study of the multi-product output of the thousand largest companies in 1952 and 1962 while less comparable to Livesay and Porter's tables verifies the trend, ibid., 156–160.

¹⁵ Gort, Diversification and Integration, 42–45.

¹⁶ Ibid., 42–45.

¹⁷ Terleckyj, Nester E., assisted by Helper, Harriet J., Research and Development, Its Growing Composition (New York, 1963)Google Scholar, quoted in Economic Concentration, Hearings, Part III, 1139.

¹⁸ Ibid., 1138.

¹⁹ Chandler, Alfred D. Jr, Strategy and Structure (Cambridge, 1962), Chapter 7Google Scholar, and “Development, Diversification, and Decentralization,” in Freeman, Ralph, ed., Postwar Economic Trends (Cambridge, 1960), Chapter 8.Google Scholar

²⁰ Concentration Ratios in Manufacturing Industries, 1963 (Washington, 1963), 2–3.

²¹ A table on increase and decrease in concentration for a much shorter period (1954–1957) in Economic Concentration, Hearings, Part III, 3, support Livesay and Porter's findings. So do the ratios given in the Concentration Ratios in Manufacturing Industry, 1963. For example, in the chemical group, the per cent value of shipments accounted for by the largest companies in four-digit industries, where information is provided, has dropped since World War II in ten industries, remained about the same in six industries, and increased only in one — toilet preparations. In electrical machinery, the per cent value has decreased substantially in transformers, motors and generators, electric welding apparatus, and phonograph records and has increased substantially in one consumer good industry — household laundry equipment — and two other industries — primary batteries and x-ray apparatus. In the machinery group, the per cent value has declined in industrial trucks and tractors, ball and roller bearings, commercial laundry machinery, and blowers and fans. And in the stone, glass, and clay group the percentage has declined in the most concentrated industries in that group, including glass containers, plumbing fixtures, asbestos products, and gaskets and insulators.

²² Their success is cited in Servan-Schreiber, Jean-Jacques, The American Challenge (New York, 1968).Google Scholar That book begins, “Fifteen years from now it is quite possible that the world's third greatest industrial power, just after the United States and Russia, will not be Europe, but American industry in Europe.”