Proof That Properly Discounted Present Values of Assets Vibrate Randomly
Abstract
Even the best investors seem to find it hard to do better than the comprehensive common-stock averages, or better on the average than random selection among stocks of comparable variability. Examination of historical samples of percentage changes in a stock's price show that, when these relative price changes are properly adjusted for expected dividends paid out, they are more or less indistinguishable from white noise, or, at the least, their expected percentage movements constitute a driftless random walk (or random walk with mean drift specifiable in terms of an interest factor appropriate to the stock's variability or riskiness). The present contribution shows that such observable patterns can be deduced rigorously from a model which hypothesizes that a stock's present price is set at the expected discounted value of its future dividends, where the future dividends are supposed to be random variables generated according to any general (but known) stochastic process. This fundamental theorem follows by an easy superposition applied to the 1965 Samuelson theorem that properly anticipated futures prices fluctuate randomly -- i.e., constitute a martingale sequence, or a generalized martingale with specifiable mean drift. Examples demonstrate that even when the economy is not free to wander randomly, intelligent speculation is able to whiten the spectrum of observed stock-price changes. A subset of investors might have better information or modes of analysis and get above average gains in the random-walk model; and the model's underlying probabilities could be shaped by fundamentalists' economic forces.Download Info
If you experience problems downloading a file, check if you have the proper application to view it first. In case of further problems read the IDEAS help page. Note that these files are not on the IDEAS site. Please be patient as the files may be large.As the access to this document is restricted, you may want to look for a different version under "Related research" (further below) or search for a different version of it.
Bibliographic Info
Article provided by The RAND Corporation in its journal Bell Journal of Economics.
Volume (Year): 4 (1973)
Issue (Month): 2 (Autumn)
Pages: 369-374
Contact details of provider:
Web page: http://www.rje.org
Order Information:
Web: http://gemini.econ.umd.edu/cgi-bin/rje_online.cgi
Related research
Keywords:References
No references listed on IDEASYou can help add them by filling out this form.
Citations
Lists
This item is featured on the following reading lists or Wikipedia pages:- Usuario:Lnegro/prueba3 in Wikipedia (Spanish)
- Principles of Finance/Section 1/Chapter 7/Efficient-Market Hypothesis in Wikibooks (English)
- Efficient-market hypothesis in Wikipedia (English)
Statistics
Access and download statisticsCorrections
When requesting a correction, please mention this item's handle: RePEc:rje:bellje:v:4:y:1973:i:autumn:p:369-374For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: ().
If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.
If references are entirely missing, you can add them using this form.
If the full references list an item that is present in RePEc, but the system did not link to it, you can help with this form.
If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your profile, as there may be some citations waiting for confirmation.
Please note that corrections may take a couple of weeks to filter through the various RePEc services.