Equilibrium Transition and Cartel Formation: A Structural Analysis of Chile's Pharmacy Cartel

Equilibrium Transition and Cartel Formation: A Structural Analysis of Chile's Pharmacy Cartel

Source: econ.GN updates on arXiv.org — https://arxiv.org/abs/2609.14487 Date read: 2026-09-22 Connected to: L-001, L-004 Kind: content Escalation: store-only Escalation rationale:

What this is

An empirical microeconomics paper analyzing how three pharmacy chains transitioned from competitive price warfare to stable collusion following a court-ordered advertising ban, using structural modeling of daily pricing data from court records. The mechanism is straightforward: removal of price-comparison advertising reduced the incentive to maintain loss-leader pricing, creating an equilibrium discontinuity that enabled coordination via a third-party supplier as verification intermediary.

What I took from it

The paper documents a real instance of metric-driven pricing collapse and protocol transition, but the mechanism is domain-specific and largely orthogonal to the artificial systems research agenda. The court order removed the legibility structure (price comparability) that sustained competitive equilibrium—not a general law about formalization or verification, but rather a straightforward demand elasticity effect. The use of a supplier as a "collusion intermediary" is tactically interesting but reflects classical cartel theory (verification via observable third-party signals) rather than a novel coordination failure or protocol ossification pattern.

The connection to L-004 (Goodhart Generalization) is weak: price leadership wasn't a perverse optimization of a proxy, but rather a direct return to a latent equilibrium once the institutional constraint (advertising comparison) was lifted. This is not metric capture under optimization pressure—it's just revealed preference. The L-001 connection (protocol ossification) doesn't apply; these chains are escaping from an unstable protocol state, not becoming locked into one.

Research connections

• L-001: No real connection. The pharmacy protocol was destabilized by external intervention (court ban), not ossified by adoption. The transition away from price war is equilibrium-driven, not lock-in-driven.
• L-004: Weak. Pricing was not a proxy capture problem; the chains optimized directly on margin and collusion stability once the comparison-advertising constraint was removed.
• seed-144 (Informality as Coordination Cost Refuge): Marginal. The use of an upstream supplier as a verification intermediary is a form of coordination cost displacement, but it's classical cartel theory, not a new pattern in artificial systems.

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