TY  - JOUR
AU  - Gabaix,Xavier
TI  - The Granular Origins of Aggregate Fluctuations
JF  - National Bureau of Economic Research Working Paper Series
VL  - No. 15286
PY  - 2009
Y2  - August 2009
UR  - http://www.nber.org/papers/w15286
L1  - http://www.nber.org/papers/w15286.pdf
N1  - Author contact info:
Xavier Gabaix
New York University
Finance Department
Stern School of Business
44 West 4th Street, 9th floor
New York, NY 10012
Tel: 212-998-0257
Fax: 212-995-4233
E-Mail: xgabaix@stern.nyu.edu
AB  - This paper proposes that idiosyncratic firm-level fluctuations can explain an important part of aggregate shocks, and provide a microfoundation for aggregate productivity shocks. Existing research has focused on using aggregate shocks to explain business cycles, arguing that individual firm shocks average out in aggregate. I show that this argument breaks down if the distribution of firm sizes is fat-tailed, as documented empirically. The idiosyncratic movements of the largest 100 firms in the US appear to explain about one third of variations in output and the Solow residual. This "granular" hypothesis suggests new directions for macroeconomic research, in particular that macroeconomic questions can be clarified by looking at the behavior of large firms. This paper's ideas and analytical results may also be useful to think about the fluctuations of other economic aggregates, such as exports or the trade balance.
ER  -