Political economy scholarship on foreign direct investment (FDI) emphasizes variation in host country political risk but overlooks variation in investors' sensitivity to political risk. We show that relational contracting, relationship‐based contract enforcement, is more efficient for high‐risk, human capital‐intensive activities for which the costs of writing legally enforceable contracts are prohibitive. We disaggregate FDI into two distinct varieties: mergers and acquisitions (M&A) and venture capital (VC). We propose that VC flows are less sensitive to host institutions but correlate strongly with skilled migrant networks that monitor compliance and impose reputational costs. Our empirical analysis of dyadic VC and M&A flows covers over 100 countries during 1980–2009. We address other mechanisms through which migrant networks facilitate FDI and verify our results hold at the country‐industry level. These findings suggest that relational contracting facilitates global integration of dynamic, knowledge‐intensive industries even when formal institutions are weak.