Supermarket monopolies have garnered significant attention in recent years. In countries like New Zealand and Australia, which exhibit low population density, only a few supermarkets manage to maintain moderate competition due to high costs and limited supply ranges.

This monopoly not only impacts consumer choice but also drives retail prices higher. To assess whether such monopolies are justified, an approach known as the "three-armed test" can be employed: first, identify existing industry structures and operational practices that require improvement; second, determine if these improvements are feasible; and third, evaluate whether the benefits outweigh the costs of any necessary changes.

If all issues can be resolved through improvement, it may indicate that the current level of monopoly is excessive. This test is not limited to the supermarket industry but can also be applied to other sectors. In New Zealand and Australia, governments are considering investigations into anti-competitive practices and exploring measures such as breaking up monopolistic firms. The implementation of these measures requires careful consideration of potential trade-offs to avoid cascading negative consequences.