Sources & endnotes.

1. 1. Long-run stock market returnsVol 2, Ch 2

   CLAIM · Since 1926, the S&P 500 has averaged roughly 10% a year before inflation; individual years are down about one year in four.

   • S&P Dow Jones Indices total-return data (spglobal.com/spdji).
   • Aswath Damodaran, “Historical Returns on Stocks, Bonds and Bills: 1928–2024,” NYU Stern School of Business (pages.stern.nyu.edu/~adamodar). Long-run nominal total return including reinvested dividends is approximately 10% per year; roughly 6–7% after inflation. Any single year commonly swings far above or below that average.

   History, not a guarantee. Past performance doesn’t predict future results, and the series’ planning illustrations deliberately use a more conservative 7% average.

2. 2. Rolling 20-year periodsVol 2, Ch 2

   CLAIM · Rolling 20-year periods of the S&P 500 have been positive every time on record — through the Depression, oil shocks, dot-com, 2008, and COVID.

   • Analyses of S&P 500 total-return data (dividends reinvested) from 1926 onward — including Crestmont Research’s 20-year rolling-return dataset (crestmontresearch.com) and First Trust’s “Historical Frequency of Positive Stock Returns” (total-return data beginning 1/31/1926) — find no negative 20-year total-return period on record. The worst 20-year stretches were low-single-digit positive; the same is true of 30-year periods.

   History, not a guarantee. A hundred years of record is evidence about the past, not a promise about the future. Individual 10-year periods HAVE been negative (1999–2008), which is one reason this money is 20-year money and never emergency-fund money.

3. 3. Day-trader loss studiesVol 2, Ch 9

   CLAIM · The large majority of active day traders lose money over time.

   • Barber & Odean, “Trading Is Hazardous to Your Wealth,” The Journal of Finance 55(2), 2000 — 66,000+ U.S. brokerage households, 1991–1996: the most active traders earned about 11.4% annually while the market returned 17.9%; the most active quintile underperformed the market by roughly 6.5 percentage points a year.
   • Barber, Lee, Liu & Odean, “Do Individual Day Traders Make Money? Evidence from Taiwan” (2004) and “The Cross-Section of Speculator Skill” (Journal of Financial Markets, 2014) — complete Taiwan Stock Exchange records: more than eight out of ten day traders lost money in a typical six-month period, and less than 1% of the day-trader population earned reliably positive returns net of fees.
   • Barber, Lee, Liu, Odean & Zhang, “Learning, Fast or Slow,” Review of Asset Pricing Studies (2020) — 1992–2006 Taiwan data: aggregate day-trader performance was reliably negative in 14 of 15 years studied.
   • Chague, De-Losso & Giovannetti, “Day Trading for a Living?” (Brazilian equity-futures market, 2020) — of individuals who persisted in day trading more than 300 sessions, 97% lost money; only about 1.1% earned more than Brazil’s minimum wage.
4. 4. MLM income studiesVol 2, Ch 9

   CLAIM · Studies of MLM participation find roughly 99% of participants lose money after expenses.

   • Jon M. Taylor, MBA, PhD, Consumer Awareness Institute, “The Case (for and) Against Multi-Level Marketing” (2011), published in the FTC’s public records (ftc.gov) — analysis of 30 recruitment-driven MLMs with available average-earnings data found participant loss rates averaging approximately 99% or more once required purchases and operating expenses are counted.
   • AARP Foundation, DeLiema et al., “AARP Study of Multilevel Marketing: Profiling Participants and Their Experiences in Direct Sales” (2018) — of surveyed U.S. participants, about 47% lost money and about 27% made no money; roughly a quarter reported any profit, and of those, more than half made under $5,000 a year. Two-thirds said they would not join again.
   • FTC, “Business Guidance Concerning Multi-Level Marketing” (ftc.gov) — the recruiting-based compensation red flag the Scam Filter’s “pyramid tell” is built on.

   Different methodologies produce different loss rates — the survey-based AARP figure is lower than the income-disclosure-based Taylor figure because it counts break-even differently. Under every published methodology, most participants make no money.

5. 5. Medical debtVol 1, Ch 8

   CLAIM · Medical debt is a leading driver of bankruptcy in America.

   • Himmelstein et al., “Medical Bankruptcy: Still Common Despite the Affordable Care Act,” American Journal of Public Health (2019) — about 66.5% of surveyed bankruptcy filers cited medical bills or illness-related income loss as a contributor. (The precise share is debated among researchers because “contributing cause” is measured differently across studies — which is why the book says “leading driver,” not “#1 cause.”)
   • KFF / Peterson-KFF Health System Tracker, “The Burden of Medical Debt in the United States” (2024 update of 2021 SIPP data) — Americans owe at least $220 billion in medical debt; KFF Health News/NPR polling finds roughly 4 in 10 adults carry some form of health-care debt.
   • Consumer Financial Protection Bureau, “Medical Debt Burden in the United States” (2022) — roughly $88 billion of medical debt appeared on consumer credit reports as of 2021.

Educational content — not financial, tax, legal, or insurance advice. Historical figures describe the past; they are not predictions. All growth projections across this series are illustrative at an assumed 7% average annual return, compounded monthly. Verify current tax and contribution figures at irs.gov and ssa.gov.