We use the case of a puzzling decline in U.S. firm antidumping (AD) filings to explore how firm-level economic heterogeneity within U.S. industries influences political and regulatory responses to changes in the global economy. Firms exhibit heterogeneity both within and across industries regarding foreign direct investment. We propose that firms making vertical, or resource-seeking, investments abroad will be less likely to file AD petitions. Hence, we argue, the increasing vertical FDI of U.S. firms (particularly in countries with undervalued currencies) makes trade disputes far less likely. We use firm level data to examine the universe of U.S. manufacturing firms and find that AD filers generally conduct no intrafirm trade with filed-against countries. Among U.S. MNCs, the number of AD filings is negatively associated with increases in the level of intrafirm trade for large firms. In the context of currency undervaluation, we confirm the existing finding that undervaluation is associated with more AD filings. We also find, however, that high levels of related-party imports from countries with undervalued currencies significantly decrease the numbers of AD filings. Our study highlights the centrality of global production networks in understanding political mobilization over international economic policy. [192]