This paper proposes a theory of excess price fluctuations in over-the-counter secondary markets. When heterogeneous assets trade under asymmetric information, a quality effect emerges: high liquidity lowers the quality of the pool of sellers and decreases future liquidity. Cyclical equilibria can arise even without fundamental shocks. In a cycle, investors speculate by bidding up the price of low-quality assets, anticipating a high resale price at the peak. When this resale effect is strong, cycles disappear and multiple steady states coexist with different levels of liquidity. The model rationalizes empirical patterns for corporate bonds and housing in particular.ASSET PRICES OFTEN APPEAR DISCONNECTED from fundamentals. This weak relationship shows as excess price fluctuations, documented notably for corporate bonds and housing by Bao and Pan (2013) and Glaeser et al. (2014). Price deviations from fundamentals are sometimes extreme during speculative episodes when prices rapidly increase before crashing (see Cutler, Poterba, and Summers 1991). In some asset classes, such as housing, the repeated nature of these episodes is puzzling. Why can price and trading volume fluctuate so much in the absence of changes to fundamentals?This paper proposes a theory of endogenous liquidity fluctuations that can rationalize these phenomena. Motivated by the markets for corporate bonds