How the Doctrine of Diversification Misses the Mark for Personal Financial Portfolios

Traditional financial wisdom says that diversification should be used to mitigate risk, by this recommendation operates only at the portfolio level. Typically, older individuals, closer to retirement age, are advised to put a greater percentage of their money in less risky investments like bonds and CDs, while younger individuals should have an aggressive, growth-oriented portfolio of mostly stocks.

However, this approach, by itself, fails to consider the underlying need for avoiding financial loss, which in many cases will never become more than unrealized loss. That is to say, as long as the money is not needed during the period the loss is occurring and ongoing, the primary benefit of diversification—the ability to withdraw money during a bear market without losing as much—is unrealized.

Fidelity’s article on diversification explains how a diversified portfolio of 70% stocks and 30% bonds and T-bills would have significantly outperformed a 100% stock portfolio from January 2008 to February 2009 (the 2008 financial crisis), with –35.0% returns instead of –49.7% returns. However, when considering wider time periods, the diversified portfolio underperforms the 100% stock portfolio. We can effectively characterize diversification as a hedge against risk, reducing volatility at the cost of decreased returns over longer time horizons.

However, one’s future discretionary income can actually be interpreted as a hedge against loss. That is, if an individual or family lives well below their means, they may be able to maintain a more aggressive portfolio, because they can fall back on their income in bear markets rather than having to cash in their investments. A danger with this approach is that financial recessions can result in layoffs and reduced income. However, if one’s income is relatively reliable (e.g., work that is somewhat “recession proof,” Social Security benefits, and certain types of pensions), this danger is mitigated. Thus, if a young-old person receiving Social Security (SS) benefits wishes to continue aggressive growth of their investments for whatever reason, they can consider their SS benefits a hedge against investment risk. For example, if they live comfortably on $50,000 per year and receive $18,000 per year in SS benefits, they only need $32,000 in additional income per year. To the extent this money must be withdrawn from aggressive investments to fund one’s living expenses, the income is a hedge against downside potential, because overall, stocks continue marching upward quite vigorously, even though they may go down in many calendar years. (I am, of course, referring to broad mutual funds rather than individual stocks or sectors.)

Research shows that trying to time the market is not an effective approach (e.g., Henriksson, 1984). Consequently, rather than trying to time the market, and without concern to tax-advantaged accounts or tax brackets with respect to withdrawals, the best time to put money in stocks is now, in a lump sum (not dollar cost averaging), and the best time to withdraw money is as far in the future as possible, as needed (that is, avoid withdrawing a lump sum when only a fraction of the money is needed at a particular time). This is because overall, the market marches upward, despite volatility along the way. Therefore, the largest gains, on average, will be yielded by placing money in aggressive investments (stocks, not bonds or CDs) for the longest continuous length of time. For most people, attempting to time the markets on either end (investing or divesting) is not only an exercise in futility, but will be detrimental.

This may sound contradictory. If I recommend avoiding market timing because it doesn’t work, why would I argue that the primary benefit of diversification can be nullified by market timing? Actually, what I am talking about is not market timing, but rather avoiding being compelled to liquidate a position due to the financial hardship during a bear market. In a recession, not only will your investment portfolio lose value—you may also lose your job or take a pay cut, your home will decline in value, et cetera. Inasmuch as the value of diversification lies in being able to liquidate better-performing assets in a recession to make up for loss of income and other extraneous factors, the value of aggressive investing lies in making increased gains overall.

Conjecture: If withdrawals are stochastic in timing, then on average, the returns from a diversified portfolio will always be inferior to a 100% stock portfolio.

The ability to use reliable discretionary income as a hedge against loss enables one to avoid compelled liquidation during a recession, which, absent emotional issues, decouples withdraw timing from market factors and consequently reduces the value of diversification. Therefore, a portfolio analysis that does not consider debts or income may have substantial opportunity costs if a client over-diversifies due to having reliable discretionary income which is not considered, or under-diversifies due to having fragile income or liabilities which are not considered. In summary, as a doctrine, diversification should be titrated with a holistic analysis of one’s overall situation.

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