Using the 2021 enforcement of China's Data Security Law and Personal Information Protection Law as an external shock, this pre-registered study seeks to explore whether—and through which channels—cross-border data flow restrictions are associated with changes in multinational enterprises' financing constraints. Employing a difference-in-differences framework combined with propensity score matching and entropy-balancing matching, we aim to examine whether the regulatory shock affects multinational enterprises' financing constraints through channels related to operational efficiency and information asymmetry. We further explore how firm characteristics, such as foreign sales intensity and state ownership, may condition these effects, with the former potentially intensifying frictions and the latter possibly providing institutional resilience.