Episode 403: Patrick Adams - When Stock Crashes Matter for Long-Term Investors

Episode Summary

Executive Summary: Patrick Adams’ research challenges the idea that working-age investors should hold 100% equities. Using U.S. tax data, he shows high-income households often sell stocks during downturns because income falls and spending is sticky, forcing liquidations at bad times. The result: emergency funds and liquidity needs matter as much as long horizons in asset allocation.

Main Topics: Why stocks are considered safe for long-term investors (Priority: 5/5): The discussion opens with the classic argument that U.S. stocks have delivered positive real returns over long horizons and recovered from crashes, supporting the 'stocks for the long run' view. When the long-run stock argument breaks down (Priority: 5/5): Patrick explains that the logic fails if investors must sell during downturns, because they miss the recovery and can permanently impair wealth. Measuring stock flows from tax data (Priority: 5/5): The paper uses administrative tax-return data and capitalization methods to infer stock purchases and sales from dividend income changes among high-income working-age households. Income risk, consumption commitments, and forced selling (Priority: 5/5): The core finding is that high-income households often face income declines during market crashes and have sticky expenses like housing, childcare, and healthcare, which forces them to draw down liquid assets. Modeling optimal portfolio choice with liquidity needs (Priority: 5/5): A lifecycle model incorporating labor-income risk, crash-linked tail risk, and consumption adjustment costs implies much lower optimal equity shares for working-age households than many prior models. Emergency funds and asset location (Priority: 4/5): The conversation reframes the result as a liquidity-management problem: households should hold safe liquid buffers, and some fixed income may belong outside retirement accounts if it is needed for emergencies.

Key Arguments: Stocks are only 'safe' for long-term investors if they can avoid selling during crashes; forced selling destroys the long-run advantage. High-income working-age households have substantial wealth, but much of it is illiquid (housing, retirement accounts, private business equity), leaving limited liquid buffers. Tax data show stock-market flows are strongly pro-cyclical: households sell more during crashes and buy more during expansions. Income shocks and stock-market crashes are linked: many high earners experience large earnings declines at the same time their portfolios fall. Consumption is sticky because a large share of budgets goes to hard-to-cut items like mortgages, housing costs, childcare, healthcare, and tuition. The model implies that the optimal equity share of liquid wealth for many working-age households is far below 100%, often around 10-40%, because they may need to spend down liquid assets in bad times. Retirees can rationally hold higher equity shares than working-age households because their income is more stable and their spending is a smaller fraction of wealth. The paper suggests that emergency funds should be thought of as part of asset allocation, not separate from it. For some households, especially those in cyclical industries or with large fixed expenses, the risk of being forced to sell stocks at the bottom is substantial. The findings differ from some prior lifecycle models because those models often assume easier spending cuts and weaker links between labor income risk and stock crashes.

Data Points: Sample period: 1998 to 2023 - Administrative tax-return data used in the paper Household group studied: Top 20% of wage and private business income within age group - Primary sample definition Share of U.S. household stock market wealth owned by sample: About one-third - High-income working-age households collectively own this share, including retirees Taxable vs retirement account stock wealth: About 50% taxable brokerage / 50% retirement accounts - How stock wealth is split for the studied group Median liquid savings for top 1% 40-year-olds: About two-thirds of pre-tax earnings, or roughly 8 months - Illustrates limited liquid buffers despite high income Top earners with large earnings declines during crashes: About 17% - Among 40-year-olds in the top 1% of earnings, during early and late 2000s crashes Average liquid stock share: About 25% - Typical share of liquid wealth invested in stocks for the sample Average retirement-account stock share: About 60% - Higher stock allocation inside retirement accounts Liquid stock share by age: Less than 20% around age 30; more than 30% around age 60 - Shows stock share rises with age in the data Housing share of annual budget: About one-third - For a typical 40-year-old high-income household Savings response to income shocks: Net savings falls by 50 to 85 cents per lost dollar of wage/business income - Households draw down liquid assets when income falls Model-implied optimal liquid equity share: About 10% to 40% - Depends on age, risk aversion, and consumption adjustment costs Baseline equity premium in model: About 5% - Normal-times assumption; higher equity premium can raise optimal stock share High-equity-premium scenario: 10% to 15% - One condition under which 100% equity can become optimal in the model Hypothetical 2008 income shock: $150,000 income drop and $100,000 drawdown - Illustrative example of forced selling during the financial crisis Hypothetical household starting point: $300,000 annual income and $200,000 liquid assets - Used to show how crash-time withdrawals reduce effective equity exposure

Pivotal Quotes: "people love research that supports 100% equity" — Cameron Passmore: Opening reaction to the paper’s challenge to conventional equity-heavy advice "stocks are only 'safe' for long-term investors if they can avoid selling during crashes" — Patrick Adams: Core logic behind why long-run stock safety can fail for households with liquidity needs "you need to have an emergency fund" — Benjamin Felix: Summary of the practical takeaway from the research

Implications: The episode argues that asset allocation should be built around liquidity risk, not just time horizon. For many working-age households, especially high earners with fixed expenses, a meaningful emergency fund and lower liquid-equity share may be more appropriate than 100% stocks.