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Bet doubling in gambling and investing

Zaneta Chapman (Arcadia University, Glenside, Pennsylvania, USA)
Thomas Getzen (Fox School of Business, Temple University, Philadelphia, Pennsylvania, USA)

Journal of Risk Finance

ISSN: 1526-5943

Article publication date: 16 August 2011




The purpose of this paper is to analyze strategies for gamblers/investors to increase their chances of reaching certain monetary and/or survival goals while facing a losing proposition.


The paper investigates the use of credit by gamblers/investors as a means of increasing their expected survival time and thus their likelihood of winning. The paper considers a strategy in which a gambler/investor engages in bet doubling and uses credit to maximize the probability of winning a specified amount.


The model presented in this paper identifies the amount of credit that will make it possible for a gambler/investor to become a winner with an arbitrarily high degree of probability, even while facing a losing proposition. However, bet doubling can lead to large losses, and negative profits can be expected if the gambler/investor is faced with unfavorable odds. As an extension, the paper considers the impact of limited liability and finds that in that case, total losses are restricted and the gambler/investor can expect a positive net gain even while facing a losing proposition. It is also shown that the cost of obtaining credit is an important consideration and that it is ill‐advised for a gambler/investor to engage in such a strategy when the cost of credit is high relative to the probability of winning.


Although bet doubling is not new to the gambling literature, this paper considers the use of credit as a means of increasing survival time and expected net gain. Applications of the model are particularly useful to gamblers/investors when credit can be obtained at low costs.



Chapman, Z. and Getzen, T. (2011), "Bet doubling in gambling and investing", Journal of Risk Finance, Vol. 12 No. 4, pp. 291-305.



Emerald Group Publishing Limited

Copyright © 2011, Emerald Group Publishing Limited

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