We find that an unanticipated tightening of US monetary policy tends to raise US import prices. This empirical "spill-back" pattern differs from the predictions of typical open-economy macro models. We also document a new empirical "spillover" effect: import prices of other countries also rise following an unexpected US monetary tightening. To understand the mechanism, we examine Chinese exporters and identify a borrowing cost channel - their liquidity conditions generally deteriorate after a US monetary tightening. Indeed, the output price response is greater for those firms facing higher borrowing costs or tighter liquidity conditions.