Concentration trends and profitability in the US manufacturing sector: 1970—84

Concentration of sales and assets of the top 25 Fortune 500 firms: 1967–90

“…In particular, the Herfindahl and the Theil indexes, both of which are used extensively for measuring concentration in business, attest to such a conclusion. This finding is also in line with the results obtained by Attaran and Saghafi (1988), wherein a trend toward concentration was evident for sales and equity for all the Fortune 500 companies and by groups of 100 companies, and for assets of the 500 and the top 100 for the period 1970-84.…”

“…The first com-' period. This pattern is also in agreement with Attaran and prises the 14 years between 1967 and 1980, called period 1, Saghafi (1988) and Saghafi and Attaran (1990). and the second comprises the 10 years between 1981 and 1990, called period 2.…”

“…Thus, several formulations for measurement have been suggested, prominent among which are the use of the variance of logarithms (Prais, 1976(Prais, , 1979Sawyer, 1979Sawyer, , 1980) and a form of Theil entropy index (Hart, 1982). The use of the latter was demonstrated in particular by Hexter and Snow (1970), Hexter (1987), Caveny (1985,1988), Attaran and Saghafi (1988) and Saghafi and Attaran (1990). In this series of articles, data concerning the largest 500 industrial corporations in the United States reported annually by Fortune were used.…”

“…O'Neill in these writings takes issue, in particular, with the works of Hexter and Snow (1970), Attaran and Saghafi (1988), Hexter (1987), and Caveny (1985, 1988) for using the Fortune data of the largest 500 industrial Downloaded by [University of California, San Diego] at 12:54 29 June 2016 firms. He proposes, instead, a computation of the share of sales of the 500 firms as ratios of the total sales data of all industrial firms for Theil's entropy index of concentration, rendering the sales of the top 500 firms as proportions of the total sales rather than as proportions of the 500 under consideration.…”

Concentration trends and profitability in US manufacturing: a further and some new (and improved) evidence

“…Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions Applied Economics, 1993Economics, , 25, 1285Economics, -1286 Concentration trends and profitability in U S manufacturing: a further comment and some new (and improved) evidence The purpose of this note is to clear up several misconceptions presented by Saghafi and Attaran (1991) (S-A), in their reply to my comment (O'Neill, 1991a). The most egregious misconception being that S-A failed to recognize the main point of my comment: the entropy index values reported by Attaran and Saghafi (1988) (A-S) are erroneous because they are based on incorrectly computed firm market share values.' In the entirety of their reply, not once d o S-A refute this claim.…”