TY  - JOUR
AU  - Caballero,Ricardo
AU  - Farhi,Emmanuel
AU  - Hammour,Mohamad L.
TI  - Speculative Growth: Hints from the US Economy
JF  - National Bureau of Economic Research Working Paper Series
VL  - No. 10518
PY  - 2004
Y2  - May 2004
UR  - http://www.nber.org/papers/w10518
L1  - http://www.nber.org/papers/w10518.pdf
N1  - Author contact info:
Ricardo J. Caballero
MIT
Department of Economics
Room E52-373a
Cambridge, MA 02142-1347
Tel: 617/253-0489
Fax: 617/253-6915
E-Mail: caball@mit.edu

Emmanuel Farhi
Harvard University
Department of Economics
Littauer Center
Cambridge, MA 02138
Tel: 617/496-1835
Fax: 617/495-8570
E-Mail: efarhi@harvard.edu

Mohamad Hammour
Delta
Ecole Nornale Superieurel
48 Boulvard Jourdan
75014 Paris
FRANCE
E-Mail: hammour@DELTA.ENS.FR
AB  - We propose a framework for understanding recurrent historical episodes of vigorous economic expansion accompanied by extreme asset valuations, as exhibited by the U.S. in the 1990s. We interpret this phenomenon as a high-valuation equilibrium with a low effective cost of capital based on optimism about the future availability of funds for investment. The key to the sustainability of such an equilibrium is feedback from increased growth to an increase in the supply of effective funding. We show that such feedback arises naturally when an expansion comes with technological progress in the capital producing sector, when fiscal rules generate sustained fiscal surpluses, when the rest of the world has lower expansion potential, and when financial constraints are relaxed by the expansion itself. Arguably, these ingredients were all simultaneously present in the U.S. during the 1990s. We also show that such expansions can be welfare improving but they can crash. The latter is more likely if bubbles develop along the expansionary path. These (rational) bubbles can emerge even when the interest rate exceeds the rate of growth of the economy.
ER  -