The cheapest way for banks to finance long term illiquid projects is typically by borrowing short term from households. But when household needs for funds are high, interest rates will rise sharply, debtors will have to shut down illiquid projects, and in extremis, will face more damaging runs. Authorities may want to push down interest rates to maintain economic activity in the face of such illiquidity, but intervention may not always be feasible, and when feasible, could encourage banks to increase leverage or fund even more illiquid projects up front. Authorities may want to commit to a specific policy of interest rate intervention to restore appropriate incentives. For instance, to offset incentives for banks to make more illiquid loans, authorities may have to commit to raising rates when low, to counter the distortions created by lowering them when high. We draw implications for interest rate policy to combat illiquidity.