Deposit volatility lowers loan maturities in presence of costly bank liquidity, which in turn reduces long-term investment and output. We formalise this mechanism in a banking model and analyse exogenous variation in deposit volatility induced by a Sharia levy in Pakistan. Data from the universe of corporate loans and a firm-level survey show that deposit volatility and liquidity cost: 1) reduce loan maturities and lending rates; 2) leave loan amounts and total investment unchanged; 3) redirect investment from fixed assets toward working capital. A targeted liquidity program is quantified to generate yearly output gains between 0.042% and 0.205%.