Exploiting a granular dataset of banks' security holdings I assess the impact of unconventional monetary policy on bank lending and security holdings. Using a difference-in-differences regression setup and holding the security composition of each bank constant at its level in January 2014, well in advance of an anticipation of the ECB's asset purchase program (APP), this paper provides evidence for the presence of a yield-induced portfolio rebalancing channel: Banks experiencing a higher average yield decline of their securities portfolio - induced by unconventional expansionary monetary policy - increase their real sector lending more strongly relative to other banks. The effect is stronger for banks facing many reinvestment decisions. Moreover, I find that banks with a higher average yield decline reduce their overall investments in securities more intensely, especially in those securities that had larger valuation gains. These novel findings suggest that banks target a specific yield level and shift their investments from the securities to the (higher-yielding) credit portfolio. Making use of data on bank-specific TLTRO uptakes, my results do not seem to be driven by alternative, liquidity-driven transmission channels.