For helpful comments, we are grateful to Francesco Agostinelli, Humlum Anders, Adrien Auclert, Job Boerma, Diego Daruich, Jesse Gregory, Kyle Herkenhoff, Erik Hurst, Rishabh Kirpalani, Paolo Martellini, Simon Mongey, and Ludwig Straub, and to several seminar participants. For outstanding research assistance, we thank Dhananjay Ghei and Bipul Verma. A preliminary version of this paper has circulated with the title “Scaling Up the American Dream: A Dynamic Analysis”.