NBER Working Papers by Alberto Martin

We explore a view of the crisis as a shock to investor sentiment that led to the collapse of a bubble or pyramid scheme in financial markets. We embed this view in a standard model of the financial accelerator and explore its empirical and policy implications. In particular, we show how the model can account for: (i) a gradual and protracted expansionary phase followed by a sudden and sharp recession; (ii) the connection (or lack of connection!) between financial and real economic activity and; (iii) a fast and strong transmission of shocks across sectors and countries. We also use the model to explore the role of fiscal policy

We develop a stylized model of economic growth with bubbles. In this model, financial frictions lead to equilibrium dispersion in the rates of return to investment. During bubbly episodes, unproductive investors demand bubbles while productive investors supply them. Because of this, bubbly episodes channel resources towards productive investment raising the growth rates of capital and output. The model also illustrates that the existence of bubbly episodes requires some investment to be dynamically inefficient: otherwise, there would be no demand for bubbles. This dynamic inefficiency, however, might be generated by an expansionary episode itself.

There is a large and growing literature that studies the effects of weak enforcement institutions on economic performance. This literature has focused almost exclusively on primary markets, in which assets are issued and traded to improve the allocation of investment and consumption. The general conclusion is that weak enforcement institutions impair the workings of these markets, giving rise to various inefficiencies. But weak enforcement institutions also create incentives to develop secondary markets, in which the assets issued in primary markets are retraded. This paper shows that trading in secondary markets counteracts the effects of weak enforcement institutions and, in the absence of further frictions, restores efficiency.

Conventional wisdom says that, in the absence of sufficient default penalties, sovereign risk constrains credit and lowers welfare. We show that this conventional wisdom rests on one implicit assumption: that assets cannot be retraded in secondary markets. Once this assumption is relaxed, there is always an equilibrium in which sovereign risk is stripped of its conventional effects. In such an equilibrium, foreigners hold domestic debts and resell them to domestic residents before enforcement. In the presence of (even arbitrarily small) default penalties, this equilibrium is shown to be unique. As a result, sovereign risk neither constrains welfare nor lowers credit. At most, it creates some additional trade in secondary markets. The results presented here suggest a change in perspective r...