Sizing the bets in a focused portfolio
Abstract: The paper provides a mathematical model and a tool for the focused investing strategy as advocated by Buffett, Munger, and others from this investment community. The approach presented here assumes that the investor's role is to think about probabilities of different outcomes for a set of businesses. Based on these assumptions, the tool calculates the optimal allocation of capital for each of the investment candidates. The model is based on a generalized Kelly Criterion with options to provide constraints that ensure: no shorting, limited use of leverage, providing a maximum limit to the risk of permanent loss of capital, and maximum individual allocation. The software is applied to an example portfolio from which certain observations about excessive diversification are obtained. In addition, the software is made available for public use.
- Buffett W. 2023. Berkshire Hathaway Shareholder Letters. https://www.berkshirehathaway.com/letters/letters.html. [Online; accessed 19 August 2023].
- Walsworth Publishing Company.
- Graham B. 2003 The Intelligent Investor. Harper Business.
- Kahneman D. 2011 Thinking, Fast and Slow. Farrar, Straus and Giroux.
- Cialdini R. 2006 Influence: The Psychology of Persuasion. Harper Business.
- Kelly J. 1956 A New Interpretation of Information Rate. Bell System Technical Journal 35, 4, 917–926.
- Pinelis M, Ruppert D. 2023 Maximizing Portfolio Predictability with Machine Learning. arXiv (Computational Finance) (doi:10.48550/arXiv.2311.01985).
- Meister, B K. 2023 Gambling the World Away: Myopic Investors. arXiv (Portfolio Management) (doi:10.48550/arXiv.2302.13994).
- Byrnes T, Barnett T. 2018 Generalized framework for applying the Kelly criterion to stock markets. International Journal of Theoretical and Applied Finance 21, 5.
- Lototsky S, Pollok A. 2020 Kelly Criterion: From a Simple Random Walk To Lévy Processes. arXiv (Computational Finance) (doi:10.48550/arXiv.2002.03448).
- Proskurnikov A, Barmish BR. 2023 On the Benefit of Nonlinear Control for Robust Logarithmic Growth:Coin Flipping Games as a Demonstration Case. arXiv (Optimization and Control) (doi:10.48550/arXiv.2303.10417).
- arXiv (Quantum Physics) (doi:10.48550/arXiv.2308.01305).
- arXiv (Portfolio Management) (doi:10.48550/arXiv.2307.13807).
- Prasad P. 2023 What I Learned About Investing from Darwin. Columbia Business School.
- Lu L. 2023. Li Lu’s Lecture at Professor Greenwald’s 2006 Class. https://www.youtube.com/watch?v=-jF5au0-JiY. [Online; accessed 2 September 2023].
- arXiv (Portfolio Management) (doi:10.48550/arXiv.2311.06519).
- arXiv (Econometrics) (doi:10.48550/arXiv.2402.01951).
- Sleep N, Zakaria Q. 2021. Nomad Investment Partnership Letters to Investors. https://igyfoundation.org.uk/wp-content/uploads/2021/03/Full_Collection_Nomad_Letters_.pdf. [Online; accessed 15 February 2024].
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