Recent trends in common stock prices suggest a distinction between increases in national net worth and¯ows of physical investment. In this paper we present a simple overlapping generations model in which such differences can arise: technological progress occurs exogenously, yet ®rms own new technologies for a time. We examine possible consequences for social security reform. Reform which increases private saving depletes part of its force raising the (capitalized) price of proprietary technologies. A calibrated example suggests an increase in physical capital one-third smaller than without inelastic factors. Both steady states and transition paths are considered.