The relevance of extrinsic uncertainty

Extrinsic uncertainty is effective at a competitive equilibrium. This is generic if spot markets are inoperative: the only objects of exchange are assets for the contingent delivery of commodities; and the asset market is incomplete. The structure of payoffs of assets may allow for non-trivial allocations invariant with respect to the extrinsic uncertainty, and the economy with a complete asset market may well have a globally unique competitive eqUilibrium. Inoperative spot markets have a natural interpretation in economies with multiple periods; assets cannot be retraded.