Abstract:
This paper proposes and demonstrates a new method for testing for predatory behavior
by incumbent oligopolists towards new entrants. Traditional tests for predation,
such as the Areeda-Turner Rule, focus on the level of price relative to average
variable cost, such that if P %3C AVC, the incumbents cannot be maximising profits
even over the short run, and so are predating. The obvious objection to these tests
(apart from difficulties in measuring variable costs) is that just about all
oligopoly models predict that price will fall after the entry of an additional
competitor: who is to say that even an unsustainable price cut is not just the
natural outcome of the market becoming structurally more competitive? We answer this
objection by taking the modelling one level deeper. We ask what type of oligopoly
'game' is being played in the market post-entry, and compare it with the pre-entry
game. If oligopoly behavior changes substantially in the direction of becoming more
'competitive', then we may have found a 'smoking gun' circumstantial evidence
pointly strongly towards predation (but falling short of directly incriminating
evidence, such as records of email conversations indicating intent to predate). Our
approach is implemented with data on the two million annual flights across the
Tasman Sea that separates the main cities of New Zealand and Australia. The market
has long been dominated by a duopoly of national carriers -- Air New Zealand and
Qantas -- who for about a year in 1995/96 faced competition from a new-firm entrant,
Kiwi International Airlines. We find that the incumbents' behavior pre-entry was
quite close to Cournot-Nash, but that it became much more competitive during the
period of triopoly competition, suggesting predation. After the exit of Kiwi,
behavior immediately became less competitive, but it did not return to pre-entry
levels, and indeed has more recently tended back towards less cooperative duopoly
pricing, perhaps to discourage any other new or existing airline from again
disturbing the market.