RECENT work has suggested that there is an association between the degree of concentration in an industry and the speed at which prices adjust to changes in prime costs (Cagan [8], Domberger [12, 13], Scherer [21], p. 356 and the references cited therein). Apart from its intrinsic interest to students of industrial economics, there would seem to be three reasons for investigating this association. First, to see what light, if any, it throws upon the influence of industrial structure on the price level together with the rate (and process) of inflation. Secondly, to test the assumption made in some influential studies (e.g. Godley and Nordhaus [15]; Coutts, Godley and Nordhaus [10] and Haig and Wood [ 18]) that the size of the lag between cost and price changes is solely dependent upon the length of the fabrication, production and delivery period in the various industries. The third reason is a 'belief', held by the author, that distributed lag coefficients in econometric studies should be subject to analysis and not left 'hanging in the air'. As part of the development of a large scale econornetric model of the Australian economy (the IMP model) a team of researchers (under the direction of Dr Brain) at Melbourne University have estimated price-prime cost equations for 43 manufacturing sectors, using annual data referring to the period 1948/49-1973/74.1 The estimating equation is of the form: