Crestmont Research found every rolling 20-year period for the S&P 500 since 1919 ended with positive total returns, pointing to long holding periods as a reliable way to beat market volatility.
That record spans major shocks including the dot-com bust, the Great Recession, the COVID-19 crash and the 2022 bear market, yet long-term investors still came out ahead.
Since January 2000, the S&P 500 has climbed 758%; a $10,000 investment in an S&P 500 ETF made then would be worth nearly $86,000 today.
The argument comes as markets hit fresh highs in August, with the S&P 500 and Dow at records and the Nasdaq Composite up nearly 18% from its April low.
Crestmont still notes outcomes depend on what investors buy, warning that risky companies with weak fundamentals may not deliver the same long-run gains.