Kelly Criterion for multiple outcomes.

Kelly Criterion for multiple outcomes
As an investor, the goal is always to maximize returns while minimizing risk. One of the most popular ways to achieve this is through the Kelly criterion, a mathematical formula used to determine the optimal size of a series of bets in order to achieve maximum growth. While the Kelly criterion is commonly used in sports betting and gambling, it is also increasingly popular in the world of finance. However, the Kelly criterion becomes more complex when dealing with multiple outcomes. In this article, we will explore the Kelly criterion with multiple outcomes and how it can be applied in investment scenarios.

Introduction.

The Kelly criterion is a betting strategy that has been around for almost 70 years. It was developed by John L. Kelly Jr. while working at Bell Labs in the 1950s. The Kelly criterion is a simple formula that determines how much money to bet in order to maximize returns. The basic idea is to bet a percentage of your bankroll based on the probability of a particular outcome. However, when there are multiple outcomes, the calculation becomes more complex.

Understanding the Kelly Criterion.

The Kelly criterion is based on the idea of maximizing the expected value of your portfolio. The expected value is the average outcome over a large number of trials. To calculate the Kelly criterion, you need to know the probability of each outcome and the payoff for each outcome. The formula is as follows:
Kelly % = (Probability of Winning x Payoff) – Probability of Losing / Payoff
This formula tells you how much of your bankroll to bet on a particular outcome. The Kelly % is the percentage of your bankroll that you should bet. The formula takes into account both the probability of winning and the payoff for winning.

The Kelly Criterion with Multiple Outcomes.

When there are multiple outcomes, the Kelly criterion becomes more complicated. In this case, you need to calculate the expected value for each possible outcome. You also need to consider the correlation between the outcomes. Correlation measures the degree to which two variables move in relation to each other. The formula for the Kelly criterion with multiple outcomes is as follows:
Kelly % = (ΣPi x Wi) / (ΣPi x Vi)
Where:
  • Pi is the probability of outcome i
  • Wi is the payoff for outcome i
  • Vi is the variance of the portfolio
The variance of the portfolio takes into account the correlation between the outcomes. The higher the correlation between the outcomes, the higher the variance of the portfolio.

Application of the Kelly Criterion in Investment Scenarios.

The Kelly criterion can be applied in investment scenarios where there are multiple possible outcomes. For example, consider a company that is considering two different investment opportunities. The first opportunity has a 60% chance of a 50% return and a 40% chance of a 20% return. The second opportunity has a 70% chance of a 30% return and a 30% chance of a 10% return.

Using the Kelly criterion formula, we can calculate the optimal investment for each opportunity.

For the first opportunity, the Kelly % would be:

Kelly % = (0.6 x 0.5) – (0.4 x 0.2) / 0.5 = 0.4 or 40%
For the second opportunity, the Kelly % would be:
Kelly % = (0.7 x 0.3) – (0.3 x 0.1) / 0.3 = 0.6 or 60%
In this scenario, the company should invest 40% of its portfolio in the first opportunity and 60% in the second opportunity in order to maximize returns.

Conclusion.

The Kelly criterion is a powerful tool for investors looking to maximize returns in a risky market. While it is commonly used in sports betting and gambling, it is also increasingly popular in the world of finance. The formula can be used to determine the optimal size of bets when dealing with multiple outcomes. However, it is important to keep in mind the limitations of the formula, such as the assumption of perfect knowledge of probabilities and payoffs.

FAQ

No, the Kelly criterion is not suitable for all investment scenarios. It is best used when dealing with a small number of outcomes where the probabilities and payoffs are well-known.

Yes, the Kelly criterion can be used in stock market investing. However, it is important to keep in mind the limitations of the formula and to use it in conjunction with other investment strategies.

The Kelly criterion differs from other investment strategies in that it takes into account the probability of each outcome and the payoff for each outcome.
The biggest disadvantage of the Kelly criterion is that it assumes that investors have perfect knowledge of the probabilities and payoffs.
Yes, the Kelly criterion can be used for long-term investing. However, it is important to adjust the formula to take into account changing probabilities and payoffs over time.