International patent surge: why do countries file patents abroad?

The globalization of economic activities increasingly compels firms to protect their technologies beyond domestic borders. While the rapid surge in international patent filings has drawn considerable attention from academics and policymakers, the underlying mechanisms dictating the spatial direction of these cross-border patent flows remain heavily debated. Relying on a structural framework of international patenting, this study first provides a theoretical decomposition to isolate the core determinants of global patent applications. We then empirically investigate the effect of bilateral trade on international patent filings utilizing an extensive panel dataset of 135 × 186 country pairs from 1995 to 2024. Our robust empirical results demonstrate that cross-border trade structurally drives international patent filings. Furthermore, we uncover profound heterogeneous dynamics: while trade and patenting act as complements in North–South and South–South relationships, they manifest as strategic substitutes among advanced North–North country pairs. Ultimately, these findings demystify the ‘market-seeking’ motives behind global intellectual property protection and significantly advance our understanding of the spatial diffusion of technological innovation.