This paper examines the role of firms’ intangible capital investments in fostering the growth of employee human capital and the subsequent spillover effects on other firms. In our model, firm investments generate improved human capital as a byproduct, allowing firms to attract workers at lower wages and creating an additional return to investment. We document a positive relationship between intangible investment and subsequent growth in workers’ portable earnings capacity, with evidence supporting a productive human-capital interpretation. We use these findings to discipline the quantitative model. Eliminating workers’ ability to differentially value firms’ learning opportunities reduces the steady-state intangible stock by 17% and aggregate income by 2.9%. For firms in the top tercile of human-capital growth, about 43% of the value generated by incubation is captured through wage savings, while the remainder accrues to workers and subsequent employers.