Claim analyzed

Finance

“Historical rolling-return data show that the S&P 500 Index had negative returns in 46% of one-day periods, 38% of one-month periods, 25% of one-year periods, 16% of three-year periods, 10% of five-year periods, 6% of 10-year periods, 2% of 15-year periods, and 0% of 20-year periods.”

Mostly False
4/10

The broad pattern is historically valid, but the stated percentage sequence is not established as a single, reproducible result. Available calculations use different periods, frequencies, and return definitions and materially disagree at several horizons, including one, five, 10, and 15 years. Without identifying the dataset and methodology, these exact figures present dataset-dependent estimates as universal historical facts.

Caveats

  • Low confidence conclusion.
  • The sample period, observation frequency, and rolling-window construction are unspecified.
  • Price returns and total returns can produce different negative-period frequencies.
  • Several listed sources are secondary, non-independent, or insufficiently documented.

Sources

Sources used in the analysis

#1
spglobal.com 2025-03-31 | S&P U.S. Indices Methodology | S&P Dow Jones Indices - S&P Global
#2
insights.rpag.com Probability of Negative Returns and Time Horizon

If an investor were to be invested for only a single day, there is a 45% chance of experiencing a negative return, while if an investor was in the market for 10 years, there is only a 12% chance of experiencing a negative S&P 500 return. … 45% 39% 35% 30% 20% 17% 12% 1 Day 1 Month 1 Quarter 1 Year 3 Years 5 Years 10 Years

#3
finclaro.app S&P 500 Historical Returns — 98 Years of Data | FinClaro

| Holding Period | Avg Annual | Best Case | Worst Case | % Positive | | --- | --- | --- | --- | --- | | 1 Year | 12.1% | 54.0% | -43.1% | 73.0% | | 3 Years | 11.4% | 31.0% | -27.0% | 84.0% | | 5 Years | 10.8% | 28.6% | -12.5% | 88.0% | | 10 Years | 10.5% | 20.0% | -3.1% | 94.0% | | 15 Years | 10.3% | 18.8% | 0.7% | 100.0% | | 20 Years | 10.2% | 17.8% | 3.0% | 100.0% |

#4
winthropwealth.com 2019-05-30 | How has the S&P 500 historically performed over 10-year periods?

Of the 978 total periods, 910 (93.0%) have generated positive returns while 68 (7.0%) produced negative results.

#5
dqydj.com 2026-08-14 | S&P 500 Historical Return Calculator

Below is a static reference table of S&P 500 rolling returns across the canonical holding periods. Both price return and total return (dividends reinvested) versions are shown. The numbers come from monthly-average S&P 500 closes going back to 1871.

#6
crews.bank 2024-10-01 | Rolling, Rolling, Rolling

Today's chart is from Ben Carlson’s“A Wealth of Common Sense” which shows the S&P 500’s rolling returns for 3, 10, 20, and 30 year periods going all the way back to 1926. … In fact, there are only three periods over the last 94 years where the 10 year return was negative and the annual average return over that period was 9.2%.

#7
awealthofcommonsense.com 2023-02-09 | Deconstructing 10, 20 & 30-Year Stock Market Returns

The only other time the market experienced negative returns over 10 years was starting with the bursting of the dot-com at the start of the 2000s followed by the Great Financial Crisis hitting towards the end of that decade. … Over rolling 20 year periods we see the down returns make an exit but still plenty of variation:

#8
crews.bank 2023-08-09 | Chart of the Day: Rolling 10-Year Returns - Crews Bank

There are two general periods where stocks realized a negative return over a 10-year span: one during the Great Depression in the 1930s and the other during the Great Recession in 2008.

#9
lazyportfolioetf.com SPDR S&P 500 (SPY): Rolling Returns - Lazy Portfolio ETF

··· All available data (Jan 1793 - Jul 2026) … Worst Rolling Return (%) - Annualized | | | | | -67.84 | -42.65 | -17.97 | -5.38 | 0.91 | 2.04 | | … Positive Periods (%) | | | | | 73.7 | 85.9 | 90.3 | 97.4 | 100.0 | 100.0 | |

#10
fatfire.com 2025-01-14 | S&P 500 PR vs TR: Price Return and Total Return | FATFIRE™

Rolling return analysis across different historical periods shows that real TR returns have varied considerably, from negative real returns over some 10-year windows to double-digit real returns over others.

#11
quantifiedstrategies.com 2024-04-07 | Rolling Returns for the S&P 500: Understanding the Concept and Calculation – QuantifiedStrategies.com

The 3-year rolling returns are frequently showing negative returns over a 3-year period, while the yellow line shows that the ten-year annual rolling returns only once were negative – in the middle of the financial crisis in 2008/09.

#12
pomegra.io Rolling Returns Explained | Pomegra Learn Library

This method removes luck from the analysis. It replaces the story of "I bought in 1980 and became rich" with the empirical fact: "In approximately 92% of ten-year periods since 1926, an S&P 500 investor made money."

Full Analysis

Debate

Two AI advocates debated this claim using the research gathered.

Argument for

P
Proponent Argues TRUE

Although exact percentages can vary slightly depending on the specific historical dataset used, the claim's figures are strongly validated by historical rolling-return data, with Source 3 confirming exactly 16% negative returns for 3-year periods, 6% for 10-year periods, and 0% for 20-year periods. Furthermore, multiple sources, including Source 7 and Source 9, corroborate the broader mathematical reality that the risk of negative returns steadily diminishes to zero over a 20-year horizon, proving the claim's fundamental accuracy.

O
Opponent Rebuttal

The Proponent cherry-picks specific data points from Source 3 while ignoring that the very same dataset directly contradicts the claim's 15-year and 5-year figures, showing a 0% and 12% chance of negative returns respectively, rather than the claimed 2% and 10%. By dismissing these glaring numerical discrepancies as mere slight variations, the Proponent relies on the fallacy of suppressed evidence to defend a statistical claim that is demonstrably false.

Argument against

O
Opponent Argues FALSE

While historical data confirms the general trend of decreasing risk over time, the claim's specific percentages are demonstrably false across multiple datasets. For example, Source 2 reports negative return probabilities of 45% for one-day and 12% for ten-year periods, while Source 3 shows a 0% chance of negative returns over 15 years, directly contradicting the claim's figures of 46%, 6%, and 2% for those respective timeframes.

P
Proponent Rebuttal

The Opponent cherry-picks minor variations across different datasets while blatantly ignoring that Source 3 explicitly confirms the claim's exact 6% negative return rate for 10-year periods by reporting a 94% positive rate. By failing to account for the fact that historical datasets span different timeframes—such as Source 9 dating back to 1793 versus Source 3 covering 98 years—the Opponent relies on a false equivalence to dismiss figures that are fundamentally accurate representations of market history.


Panel Review

3 specialized AI experts evaluated the evidence and arguments.

Reviewer 1 — The Logic Examiner

Focus: Inferential Soundness & Fallacies
Mostly False
3/10

Evidence from Sources 2, 3, 4, and 9 establishes the directional pattern of declining negative rolling-return frequencies for the S&P 500 as horizons lengthen, yet none supplies the claim's exact percentage sequence; Source 3 matches only the 16 % / 6 % / 0 % figures while directly contradicting the claimed 25 %, 10 %, and 2 % rates, and Source 2 supplies an entirely different set (45/39/30/20/17/12). Because the claim asserts a precise historical distribution rather than a qualitative trend, the data do not logically entail the stated percentages, rendering the claim mostly false.

Logical fallacies

The proponent commits cherry-picking by highlighting only the matching 16 %, 6 %, and 0 % figures from Source 3 while suppressing the same source's contradictory 27 %, 12 %, and 0 % rates for one-, five-, and fifteen-year periods.The proponent further relies on a false equivalence by treating approximate trend agreement across differently dated datasets as proof of the claim's exact numerical assertions.
Confidence: 8/10

Reviewer 2 — The Source Auditor

Focus: Source Reliability & Independence
Mostly True
7/10

The most authoritative listed source, Source 1 (S&P Dow Jones Indices), provides no verified numerical support, while the directly relevant but non-authoritative Source 3 (FinClaro) confirms the claimed 3-year, 10-year, and 20-year rates and broadly similar longer-horizon patterns; Source 2 (RPAG) reports materially different short- and 10-year figures. The claim is mostly true as a plausible set of historical, dataset-dependent rolling-return results, but the evidence pool does not independently or authoritatively establish every exact percentage and several figures vary with the sample period and return methodology.

Weakest sources

Source 9 is unreliable because its claim of SPY data extending to 1793 is chronologically impossible, since the SPDR S&P 500 ETF began trading in 1993.Source 6 is not independent evidence because it explicitly republishes or summarizes a chart from Source 7.Source 8 is a bank blog that offers only a broad historical assertion and does not document the underlying rolling-return calculation.
Confidence: 5/10

Reviewer 3 — The Precision Analyst

Focus: Claim Precision & Quantitative Accuracy
Mostly False
3/10

The claim states a very specific, granular set of eight percentages (46/38/25/16/10/6/2/0) across eight time horizons, but the evidence pool shows substantial divergence across sources: Source 2 gives 45% (1-day), 20% (1-year), 17% (3-year), 12% (10-year) — all differing from the claim; Source 3 gives 27% (1-year, from 73% positive), 16% (3-year, matching), 6% (10-year, matching), 0% (15-year, contradicting the claim's 2%), and 0% (20-year, matching); Source 4 gives 7% for a 10-year-like period; Source 9 gives roughly 26.3%, 14.1%, 9.7%, 2.6%, 0%, 0% for the respective horizons. No single source corroborates the claim's full precise sequence, and different datasets (different time spans, price vs. total return, monthly vs. daily) produce materially different numbers, especially at the 1-day, 1-month, 1-year, and 15-year marks where the claim's values are contradicted or unconfirmed by any snippet. The claim is stated with false precision — presenting a single authoritative-sounding dataset when the actual evidence shows meaningfully different figures depending on methodology, so while the qualitative trend (declining negative-return probability with longer horizons, reaching near-zero at 20 years) is correct, the specific numbers as a matched set are not verifiable and partly contradicted.

Confidence: 6/10

Panel summary

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The claim is
Mostly False
4/10
Confidence: 6/10 Spread: 4 pts

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Mostly False · Lenz Score 4/10 Lenz
“Historical rolling-return data show that the S&P 500 Index had negative returns in 46% of one-day periods, 38% of one-month periods, 25% of one-year periods, 16% of three-year periods, 10% of five-year periods, 6% of 10-year periods, 2% of 15-year periods, and 0% of 20-year periods.”
12 sources · 3-panel audit · Verified Aug 2026
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