A method is proposed to aggregate product-by-product elasticities over groups of products so as to obtain aggregate group-by-group elasticities. It is shown that price-cost margins charged by multi-product firms can be written as minus an aggregate inverse elasticity, just as the traditional...

There are two standard versions for one-shot oligopoly games: the Cournot game and the Bertrand game. The common feature is that in both games the strategic variables are supply curves. Under Cournot the supply curves are vertical lines in price-quantity space, under Bertrand they are horizontal...

Whether a two-sided platform faces a critical-mass problem in its start-up phase depends on how difficult it is to get each of the sides on board when the other side is not yet there – the so-called chicken-and-egg problem. If there is no chicken-and-egg problem, there is no critical-mass...

Collusion, particularly collusion is in the form of hardcore cartel behavior, is the worst antitrust offense of all. People engaging in such conduct should be punished severely. That is the consensus among antitrust officials. I argue against, that collusion is not that bad as antitrust...

In his article “Two-Sided Vs. Complementary Products” Filistrucchi explains in what respect two-sided platforms are different from firms producing complementary products, in spite of the similarity in pricing strategies. For him, the distinguishing feature of two-sided platforms is the...

Production costs play a crucial role in competition policy and price regulation. A shared purpose of both policies is to keep prices close to production costs to the benefit of the consumers and of the society as a whole. The problem is that prices are per product and costs are per firm. So, the...

In a recent article, Daljord, Sørgard, and Thomassen criticize Katz and Shapiro for applying the standard formula for critical loss to the case in which the price of only one product of the candidate market is increased. They argue that the standard formula does not hold in that case and...