Issue
EPL
Volume 84, Number 6, December 2008
Article Number 68003
Number of page(s) 6
Section Interdisciplinary Physics and Related Areas of Science and Technology
DOI http://dx.doi.org/10.1209/0295-5075/84/68003
Published online 12 January 2009
EPL, 84 (2008) 68003
DOI: 10.1209/0295-5075/84/68003

Fluctuations of company yearly profits vs. scaled revenue: Fat-tail distribution of Lévy type

H. E. Roman1, R. A. Siliprandi1, Ch. Dose2, C. Riccardi1 and M. Porto3

1   Dipartimento di Fisica, Università di Milano-Bicocca - Piazza della Scienza 3, 20126 Milano, Italy, EU
2   Hewlett-Packard - Via Giuseppe Di Vittorio 9, 20063 Cernusco sul Naviglio (MI), Italy, EU
3   Institut für Festkörperphysik, Technische Universität Darmstadt - Hochschulstr. 8, 64289 Darmstadt, Germany, EU

eduardo.roman@mib.infn.it

received 29 September 2008; accepted in final form 19 November 2008; published December 2008
published online 12 January 2009

Abstract
We analyze annual revenues and earnings data for the 500 largest-revenue U.S. companies during the period 1954–2007. We find that mean year profits are proportional to mean year revenues, exception made for few anomalous years, from which we postulate a linear relation between company expected mean profit and revenue. Mean annual revenues are used to scale both company profits and revenues. Annual profit fluctuations are obtained as difference between actual annual profit and its expected mean value, scaled by a power of the revenue to get a stationary behavior as a function of revenue. We find that profit fluctuations are broadly distributed having approximate power law tails with a Lévy-type exponent $\alpha$ $\simeq$ 1.7, from which we derive the associated break-even probability distribution. The predictions are compared with empirical data.

PACS
89.65.Gh - Economics; econophysics, financial markets, business and management.
05.45.Tp - Time series analysis.
05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.

© EPLA 2008