TABLE 21.-Change between 1947 and 1958 in the percent of value of shipments accounted for by the 4 largest companies in 1947 and the 4 largest companies in 1958, for selected industries-Continued 1958 Percentage Rank of 4 larg est com. 1947 cent of point change, cent total of total 19477 1 The SIC (4 digit) industry descriptions used in this report are based on the classification system used through 1957 and will differ from those appearing in the 1958 Census of Manufactures Reports, series MC-20 through MC-39. For a description of the industries in this report, see the appropriate 1954 Census of Manufactures Industry Report or the 1958 Census of Manufactures Preliminary Reports MC(P)-20 through MC (P)-39. Includes, for all manufacturing establishments classified in the industry, not only (a) their value of products "primary" to the industry, but also (b) their value of "secondary" products, which are primary to other industries, and (c) their "miscellaneous receipts" such as receipts for contract and commission work on materials owned by others, scrap and salable refuse, repair, etc. Excludes sales of products bought and resold in the same condition. The determination of company affiliation of establishments is based on census reports and publicly available records. Value of shipments totals for establishments have been summarized into company totals in each manufacturing industry. "Largest" companies are determined by each company's value of shipments in the specified industry. The percentages consist of the sum of the value of shipments of the largest four companies, divided by the total value of shipments of the industry, in the specified year. Represents the change in the percent of the value of shipments accounted for by the four companies which were largest in the industry in 1947. Represents the change in the percent of the value of shipments accounted for by the four companies which were the largest in the industry in 1958. The letter codes used represent the following situations: (A) The four largest companies in 1947 were also the four largest in 1958 and were ranked in the same order in both years. (13) The four largest companies in 1947 were also the four largest in 1958, but there was some shifting in rank. (C) The four largest companies in 1947 were not all among the four largest companies in 1958. Thus, at least one of the four largest in 1947 was no longer among the four largest in 1958. For this industry, value added was used to calculate the concentration ratios for the four largest companies rather than value of shipments because the latter contains a substantial and unmeasurable amount of duplication. TABLE 22.-Distribution of selected industries, by concentration ratio for 4 largest companies in 1958, based on value of shipments, by change in concentration ratio from 1947 to 1958 for identical largest companies, and by size of employment in 1958 TABLE 23.-Distribution of selected industries, by concentration ratio for 4 largest companies in 1958 based on value of shipments, and by change in concentration ratio from 1947 to 1958 for identical largest companies TABLE 24.-Distribution of selected industries, by concentration ratio for 4 largest companies in 1947 based on value of shipments, by change in concentration ratio from 1947 to 1958 for identical largest companies, and by size of employment in 1958 [Number of industries] Industry size class (employment in 1958) and change in concentration ratio from 1947 to 1958 Total..... 100,000 or more employees: Increase of 8 percentage points or more... Decrease of 3 to 7 percentage points.. Decrease of 8 percentage points or more... 50,000 to 99,999 employees: Increase of 8 percentage points or more.... of 2 percentage points.. Decrease of 3 to 7 percentage points. 20,000 to 49,999 employees: Increase of 8 percentage points or more.... 1 4 1 625 25 1 2 10 121 5 1 1 3 Decrease of 3 to 7 percentage points. 748 2 18 2 10,000 to 19,999 employees: 145 Decrease of 3 to 7 percentage points. Decrease of 8 percentage points or more.. TABLE 25.-Distribution of selected industries, by concentration ratio for 4 largest companies in 1947 based on value of shipments, and by change in concentration ratio from 1947 to 1958 for identical largest companies Change in concentration ratio from 1947 to 1958 Total 80 to 70 to 60 to 50 to 40 to 30 to 20 to Less 100 Table 26.—Composition of 4 leading companies, based on value of shipments, in selected industries in 1958 compared to 1947, by industry group TABLE 27.-Composition of 4 leading companies, based on value of shipments, in selected industries in 1958 compared to 1947, by industry employment size TABLE 28.-Composition of 4 leading companies, based on value of shipments, in selected industries in 1958 compared to 1947, by concentration ratio Tables 29-34 The following tables present some information on the manufacturing activities of the largest manufacturing companies in 1958, for which shares of total manufacturing value added were calculated for tables 1-A-1-G in part I. For tables 29-32, the 100 largest manufacturing companies in 1958 based on value added were identified and matched to the 8 largest companies in each product class or product group. These 100 largest companies are the same as those included in tables 1-A and 1-B, part I. In order to minimize the possibility of disclosing operations of individual companies in table 33, the special combinations of industries developed by the Bureau of the Census to compile companylevel statistics were used. These categories are often equivalent to three-digit SIC groupings. A thorough description of the categories and the criteria used to develop them appears in the 1954 Census of Business, Manufactures, and Minerals report CS-1, "Company Statistics," and the 1958 census report "Enterprise Statistics, 1958, Part I: Company Statistics." In order to provide comparability to the other concentration data presented on an employment basis in table 3 of part I, tables 33 and 34 are on an old SIC basis. This presented somewhat of a problem because the census company statistics tabulations were originally prepared on a new SIC basis. To convert to the old SIC, the 1958 company and establishment new SIC totals were reallocated among the company industry categories used in 1954. Much of the noncomparability between the old and the new SIC disappeared at this summary level. To reduce the remaining noncomparability, old SIC codes previously assigned to the establishment reports were used to reclassify large establishments or companies which would have been coded differently under the old and new SIC. The 82 manufacturing categories in table 33 have been coded to indicate the degree of comparability of the total employment derived by this method to that derived by summarizing the total employment of all establishments coded on the old SIC basis. In table 33 the 1958 employment at the manufacturing establishment of the 200 largest companies has been distributed according to the industry classification of those establishments. The employment of all establishments in the each-industry category is also presented and the share of the establishment of the large companies calculated. In table 34 the total employment of each company has been assigned to a single two-digit industry group according to the primary activity of the company as a whole. In this company coding procedure, the company is first classified into one of the major economic divisions (manufacturing, wholesale, retail, service, minerals) on the basis of payrolls. Manufacturing and minerals companies are then classified into one of the two-digit categories on the basis of value added. In |