DYNAMIC INEFFICIENCY, ENDOGENOUS GROWTH, AND PONZI GAMES

We show that in competitive endogenous growth models without externalities, balanced growth equilibria are dynamically efficient. With learning-by-doing externalities, dynamic inefficiency may exist, but due to the mix of capital rather than its scale. These results are obtained independent of whether or not lifetimes are finite or generations overlap. In OLG models with externalities we show that Ponzi games may be feasible even though equilibria are characterized by undersaving.