چكيده لاتين :
This paper originates the theory of buyer concentration for a
main raw material input for a single processing industry. The
oilgopsony concentration is obtained and subsequently decomposed
into several factors, affecting indirectly the industryיs profitability.
It is found that the leading firmsי efficiencies hypothesis is
reaffirmed due to variations associated with the marginal
productivity differentials. This finding is based on concentration
separation approach rather than analyzing the cost-efficiency effect against market power effect from increasing concentration on the
industryיs markup, provided by structural approach of minimum
cost function.
