WTO rules prohibit "disguised protection" in the form of domestic policies. How then do governments cooperate over trade and domestic policies when none can verify whether a nation's domestic tax reduction is a protective measure or a reaction to a production externality? In this paper, each government privately observes whether a production externality associated with its import-competing good is high or low. This paper finds that in an optimal agreement, disguised protection with domestic policies is never used by governments with a high externality, and is never commonly realized. Moreover, in an optimal agreement, tariffs may be conditional on domestic policies.

The paper studies monopoly pricing of a vertically differentiated durable good in a two-period model. It provides an explanation for seemingly unusual practice of a firm selling a "degraded good," arguing that the presence of Coasian dynamics may lead to the sale of the degraded good that is not less costly to produce than a high-quality good. The main finding is that when the firm can identify previous customers only if they voluntarily reveal their past purchases, it sells the degraded good along with the high-quality good in the first period. When the firm sells an upgrade of the degraded good, the price of the high-quality good cannot be "too low" in the second period, since otherwise the upgrading customers would pretend to be new customers. Thus the firm can enhance first-period sales while mitigating consumers' incentive to wait until the next period.

We consider non-price advertising by retail firms that are privately informed as to their respective production costs. We construct an advertising equilibrium, in which informed consumers use an advertising search rule whereby they buy from the highest-advertising firm. Consumers are rational in using the advertising search rule, since the lowest-cost firm advertises the most and also selects the lowest price. Even though the advertising equilibrium facilitates productive efficiency, we establish conditions under which firms enjoy higher expected profit when advertising is banned. Consumer welfare falls in this case, however. Under free entry, social surplus is higher when advertising is allowed. In addition, we consider a benchmark model of price competition; we provide comparative-statics results with respect to the number of informed consumers, the number of firms and the distribution of costs; and we consider the possibility of sequential search.

We consider non-price advertising by retail …rms that are privately informed as to their respective production costs. We …rst analyze a static model. We construct an advertising equilibrium, in which informed consumers use an advertising search rule whereby they buy from the highest-advertising …rm. Consumers are rational in using the advertising search rule, since the lowest-cost …rm advertises the most and also selects the lowest price. Even though the advertising equilibrium facilitates productive e¢ ciency, we establish conditions under which …rms enjoy higher expected pro…t when advertising is banned. Consumer welfare falls in this case, however. We next analyze a dynamic model in which privately informed …rms interact repeatedly. In this setting, …rms may achieve a collusive equilibrium in which they limit the use of advertising, and we establish conditions under which optimal collusion entails pooling at zero advertising. More generally, full or partial pooling is observed in optimal collusion. In summary, non-price advertising can promote product e¢ ciency and raise consumer welfare; however, …rms often have incentive to diminish advertising competition, whether through regulatory restrictions or collusion.

In this paper, we develop a model of collusion in which two firms play an infinitelyrepeated Bertrand game when each firm has a privately-informed agent. The colluding firms, fixing prices, allocate market shares based on the agent's information as to cost types. We emphasize that the presence of privately-informed agents may provide firms with a strategic opportunity to exploit an interaction between internal contracting and market-sharing arrangement: the contracts with agents may be used to induce firms' truthful communication in their collusion, and collusive market-share allocation may act to reduce the agents' information rents.Journal of Literature Classification numbers: C73, L13, L14.