Composable finance

Composability - open interactions between assets and protocols - facilitates a modular financial architecture. I document the emergence of composed asset transformation, where tokenized assets are rebundled to alter access, liquidity, and risk characteristics to broaden and enhance the set of tokenized U.S. dollar instruments. Yet, I argue that "naive" composability fundamentally conflicts with the provision of pooled arrangements needed for liquidity provision, risk-sharing, and capital backstops. I demonstrate this in an economy consisting of a vertical chain of protocols. Upper-layer protocols expand access to users, but bootstrap contingent liquidity from lower-layer protocols, resulting in a waterfall of externalities. In equilibrium, the base protocol rations liquid reserves, resulting in systemic illiquidity across the economy. Under severe circumstances, total utilization shrinks with composability. I offer principles and direction for building a sustainable, composable system.