We study a labor market equilibrium model in which firms sign optimal long-term contracts with workers. Firms that are financially constrained offer an increasing wage profile: They pay lower wages today in exchange of higher future wages once they become unconstrained. Because constrained firms grow faster, the model predicts a positive correlation between the growth of wages and the growth of the firm. Under some conditions, the model also generates a positive relation between firm size and wages. Using matched employer-employee data from Finland and the National Longitudinal Survey of Youth for the US, we show that the key dynamic properties of the model are supported by the data.