Do SEP injunctions alter market shares? Causal evidence from the Nokia–OPPO dispute in Europe

This study examines whether standard essential patent (SEP) injunctions reshape the European smartphone market structure. Using the 2022Q3 German injunction against OPPO as a natural experiment, we construct a brand × country × quarter panel across five major European markets (2021–2024). Employing a Difference-in-Differences (DiD) model with brand × country and quarter fixed effects, complemented by event study approach, we identify the injunction’s impact on market share. According to the results, the patent litigation leads to a significant decline in the market share of the treatment group, which confirms the negative impact of SEP litigation on the market performance of the vendors. The conclusions remain robust to the replacement of the explanatory variable, different event windows, placebo periods, and wild-cluster bootstrap inference.