[We study market efficiency in an infinite-horizon model with a monopolistic insider. The insider can trade with competitive market makers and noise traders, and observes privately the expected growth rate of asset dividends. In the absence of the insider, this information would be reflected in prices only after a long series of dividend observations. Thus, the insider's information is "long-lived." Surprisingly, however, the monopolistic insider chooses to reveal her information very quickly, within a time converging to zero as the market approaches continuous trading. Although the market converges to strong-form efficiency, the insider's profits do not converge to zero.]

We study market efficiency in an infinite-horizon model with a monopolistic insider. The insider can trade with a competitive market maker and noise traders, and observes privately the expected growth rate of asset dividends. In the absence of the insider, this information would be reflected in prices only after a long series of dividend observations. The insider chooses, however, to reveal the information very quickly, within a time converging to zero as the market approaches continuous trading. Although the market converges to strong-form efficiency, the insider's profits do not converge to zero.

ABSTRACT We propose a model in which assets with identical cash flows can trade at different prices. Infinitely lived agents can establish long positions in a search spot market, or short positions by first borrowing an asset in a search repo market. We show that short‐sellers can endogenously concentrate in one asset because of search externalities and the constraint that they must deliver the asset they borrowed. That asset enjoys greater liquidity, a higher lending fee (“specialness”), and trades at a premium consistent with no‐arbitrage. We derive closed‐form solutions for small frictions, and provide a calibration generating realistic on‐the‐run premia.