If an increase in labor supply makes capital more productive, firms respond to immigration by investing—but only if they can finance it. I study how credit-market frictions shape firms’ investment response to immigration- induced labor supply shocks and its consequences for native workers’ earnings. In a model of immigration’s labor market effects where firms face an external finance premium, initially higher-leverage firms face steeper credit supply curves and borrow less in response to a labor supply shock, so their capital-labor ratios and their incumbent workers’ earnings fall by more. Germany during the 2010s fits this pattern: capital-labor ratios declined after the onset of a decade-long immigration shock, and more sharply among initially high-leverage firms, whose borrowing costs were more sensitive to additional debt. Exploiting variation across commuting zones in the settlement patterns of earlier immigrants, I find that immigration raised capital investment and new borrowing by less, and reduced native wages and employment by more, for firms with higher initial leverage. Firms’ balance sheets are thus an important mediator of the labor market effects of immigration.
