We present a model in which endogenous liquidity generates a feedback loop between secondary market liquidity and firm's financing decisions in primary markets. The model features two key frictions: a costly state verification problem in primary markets, and search frictions in over-the-counter secondary markets. Our concept of liquidity depends endogenously on illiquid assets put up for sale by impatient investors relative to the resources available for buying those assets. The endogenous nature of liquidity creates a feedback loop as issuance in primary markets affects secondary market liquidity, and vice versa through liquidity premia. We show that the privately optimal allocations are inefficient because investors and firms fail to internalize how their respective behavior affects secondary market liquidity. These inefficiencies are established analytically through a set of wedge expressions for key efficiency margins. Our analysis provides a rationale for the effect of quantitative easing on secondary and primary capital markets and the real economy.