This paper examines how the network of supply chain propagates future operating shocks. For this purpose, we first build a network of supply chain by merging customer information directly extracted from 10-K statements in conjunction with the Compustat customer segment database. We also construct a wide range of similarity indices that identify firm-level shocks to future operating outcomes by comparing year-on-year 10-K/Q filings. We then map these future operating shocks into the supply chain network to empirically test their spillover effects. Our empirical analysis shows significantly negative spillover effects of the future operating shocks on firms’ revenues at least two connections away from the origin. Our findings contribute to literature by supporting and quantifying externalities and spillovers along firm connections.