Pitfalls in tests for changes in correlations
Correlations are crucial for pricing and hedging derivatives whose payoff depends on more than one asset. Typically, correlations computed separately for ordinary and stressful market conditions differ considerably, a pattern widely termed "correlation breakdown." As a result, risk managers worry that their hedges will be useless when they are most needed, namely during "stressful" market situations. ; We show that such worries may not be justified since "correlation breakdowns" can easily be generated by data whose distribution is stationary and, in particular, whose correlation coefficient is constant. We make this point analytically, by way of several numerical examples, and via an empirical illustration. ; But, risk managers should not necessarily relax. Although "correlation breakdown" can be an artifact of poor data analysis, other evidence suggests that correlations do in fact change over time, though not in a way that is correlated with "stressful" market conditions.
|Date of creation:||1997|
|Date of revision:|
|Contact details of provider:|| Postal: 20th Street and Constitution Avenue, NW, Washington, DC 20551|
Web page: http://www.federalreserve.gov/
More information through EDIRC
|Order Information:||Web: http://www.federalreserve.gov/pubs/ifdp/order.htm|
Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
- Karolyi, G Andrew & Stulz, Rene M, 1996.
" Why Do Markets Move Together? An Investigation of U.S.-Japan Stock Return Comovements,"
Journal of Finance,
American Finance Association, vol. 51(3), pages 951-86, July.
- G. Andrew Karoly & Rene Stulz, . "Why do Markets Move Together? An Investigation of U.S.-Japan Stock Return Comovements," Research in Financial Economics 9603, Ohio State University.
- Campa, J.M. & Chang, P.H.K., 1995.
"The Forecasting Ability of Correlations Implied in Foreign Exchange Options,"
95-26, Columbia - Graduate School of Business.
- Campa, Jose Manuel & Chang, P. H. Kevin, 1998. "The forecasting ability of correlations implied in foreign exchange options," Journal of International Money and Finance, Elsevier, vol. 17(6), pages 855-880, December.
- Jose M. Campa & P. H. Kevin Chang, 1997. "The Forecasting Ability of Correlations Implied in Foreign Exchange Options," NBER Working Papers 5974, National Bureau of Economic Research, Inc.
- Bollerslev, Tim, 1990. "Modelling the Coherence in Short-run Nominal Exchange Rates: A Multivariate Generalized ARCH Model," The Review of Economics and Statistics, MIT Press, vol. 72(3), pages 498-505, August.
- Andrews, Donald W. K., 1987.
"Laws of Large Numbers for Dependent Non-Identically Distributed Random Variables,"
645, California Institute of Technology, Division of the Humanities and Social Sciences.
- Andrews, Donald W.K., 1988. "Laws of Large Numbers for Dependent Non-Identically Distributed Random Variables," Econometric Theory, Cambridge University Press, vol. 4(03), pages 458-467, December.
When requesting a correction, please mention this item's handle: RePEc:fip:fedgif:597. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Marlene Vikor)
If references are entirely missing, you can add them using this form.