Missing The S&P 500’s Best 10 Days Over 20 Years Cuts A $10,000 Investment’s Value By More Than Half, Data Shows

A $10,000 investment in the State Street SPDR S&P 500 ETF Trust (NYSEARCA: SPY) made on October 12, 2006, grew to approximately $82,300 by October 12, 2026, with dividends reinvested.

Strip out just the fund’s 10 best trading days over that 20-year period, however, and that same initial investment finishes at only around $35,700.

Those 10 days, drawn from more than 5,000 total trading sessions, account for roughly 57% of the ending value of a fully invested position.

The fully invested portfolio compounded at approximately 11% annually, while removing the 10 best days causes that annual return to fall to under 7%.

Excluding the best 20 days drops the ending value further to around $21,500, and an investor who missed the 40 best days would have finished with roughly $9,900, barely recovering the original investment after two decades.

The S&P 500 recently closed at a record high and is currently trading at around 26 times earnings, compared to a 10-year average of approximately 24 times, according to FactSet.

With valuations elevated, some investors may be tempted to move to the sidelines and wait for a pullback before re-entering the market, but the historical data illustrates how severely that strategy can backfire.

Six of the 10 best days for the State Street fund occurred between October 2008 and March 2009, during the depths of the global financial crisis.

Three additional top-performing days came in March and April 2020, as the COVID-19 pandemic was forcing widespread economic shutdowns across the country.

Most of those 10 best days occurred within two weeks of one of the market’s worst single-day performances, reinforcing how tightly gains and losses cluster during periods of peak volatility.

The State Street SPDR S&P 500 ETF Trust was selected for this analysis because it was the first exchange-traded fund listed in the United States, having launched in January 1993, giving it a complete 20-year daily price history for comparison.

Investors who attempt to time the market risk sitting on the sidelines during precisely the sessions that deliver the most powerful recoveries, permanently impairing long-term returns in the process.