textThis first essay reconsiders how a central bank might tailor its monetary policy in response to a liquidity shortage problem that arises from payments system design. Short run monetary intervention that completely mitigates liquidity shortage achieves Pareto optimality. However, it is not Pareto improving: by inducing shifts in agents’ portfolio choice, short run monetary policy alters the long term real interest rate, and consequently, the distribution of consumption goods among heterogeneous agents. A regime that pays interest on reserves could attain Pareto improving allocation, but is never Pareto optimal. Under the interest on reserves scheme, the central bank can pursue policy targeting the quantity of reserves balances fo...