Financial Wisdom Isn't Cyclical: How to Make Better Portfolio Decisions

 | Nov 29, 2023 13:43

Financial “wisdom” is said to be cyclical rather than cumulative, but that’s unfair. At least in the dominion of portfolio management and design, academics and money managers have made great strides in decoding Mr. Market’s cryptic signals over the past half-century. The challenge, having led the proverbial horse to water, is making him drink.

The stakes are high. History, in fact, suggests that missed opportunity costs are immense, notes “The Missing Billionaires: A Guide to Better Financial Decisions”, a new book by Victor Haghani and James White, who run Elm Wealth, a wealth management firm. Using the 19th-century industrialist Cornelius Vanderbilt as an example, the authors report: When Vanderbilt died in 1877, he was the wealthiest man in the world, and his son, Billy, inherited 95% of his father’s assets. “Within 70 years of the Commodore’s death, the family wealth was largely dissipated. Today, not one Vanderbilt descendant can trace his or her wealth to the vast fortune Cornelius bequeathed.”

What happened? The short answer: is poor wealth management. More precisely, poor design and management of the investment portfolio, are exacerbated by equally poor judgment in overseeing the deaccumulation (spending) decisions.

Financial advisory has improved since the Gilded Age created vast fortunes, but short-sighted decisions in wealth management are a hardy perennial. Haghani and White cite data published by Forbes that estimates in 2022 “there were just over 700 billionaires in the United States, and you’ll struggle to find a single one who traces his or her wealth back to a millionaire ancestor from 1900.” In fact, “Fewer than 10% of today’s US billionaires are descended from members of the first Forbes 400 Rich List published in 1982. Even the least wealth family on that 1982 list, with ‘just’ $100 million, should have spawned four billionaire families today.”

Even after accounting for dedicated efforts to give away wealth, the absent billionaires is surprising. “Our point is that, collectively, we all face a really big and pervasive problem when it comes to making good financial decisions.”

The pitfalls that led to the so-called missing billionaires include some obvious mistakes, such as being too aggressive with risk-taking and spending too much too fast. Arguably the most important decision, and one that’s a core focus of the book, is what’s known as the sizing decision – the optimal share of wealth to deploy to risk assets, or the equivalent for determining how much to spend at intervals through time. Estimating this share is “the most critical part of investing,” the authors write.

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The good news is that research on the sizing decision has a long pedigree, starting in the modern era, Haghani tells The Capital Spectator in a recent interview. It starts with John von Neumann’s game theory research in the 1940s. The basic goal, he explains: “Maximize expected wealth on a risk-adjusted basis – putting a cap on maximum level of risk.”

A quantitative solution for investment sizing decisions was outlined in 1956 by John Kelly (the Kelly criterion) and later, from a somewhat different perspective, by Robert Merton in 1969 via what’s known as the Merton share. A fair amount of “The Missing Billionaires” analyzes the implications of the latter, and rightly so, since it’s a cornerstone of informed portfolio design and management. In fact, the book’s deft review and deconstruction of the Merton share methodology elevates “The Missing Billionaires” to the must-read short list of books of recent vintage within the investment genre.

At a basic level, the Merton share formula is as elegant as it is simple: