The S&P 500 has delivered average annual returns of roughly 10% over the past 98 years, weathering countless economic crises, recessions, and market crashes along the way.
That long-term track record makes broad index investing one of the most reliable wealth-building strategies available to everyday investors seeking financial independence.
The State Street SPDR Portfolio S&P 500 ETF (NYSEMKT: SPYM) has built a compelling case for itself as one of the most cost-efficient ways to access that kind of long-run market performance.
Over the past 20 years since its inception in November 2005, SPYM has delivered average annual returns of 11.26%, outpacing the historical S&P 500 average and rewarding patient, long-term investors.
The fund holds approximately $172.5 billion in assets and charges an expense ratio of just 0.02%, making it one of the lowest-cost index funds available to retail investors today.
SPYM tracks the S&P 500, which represents 500 of the largest publicly traded companies in the United States and accounts for roughly 80% of the entire U.S. stock market by market capitalization.
The S&P 500 recently hit all-time highs and is up about 13% year to date in 2026, even amid short-term turbulence tied to the Iran conflict and ongoing concerns about inflation and rising interest rates.
SPYM has also delivered strong shorter-term results, with annualized returns of about 15.1% over the past decade, 12.8% over the past three years, and 19.3% over the past year.
Assuming SPYM continues to deliver its 20-year average annual return of 11.26%, an investor contributing $500 per month would accumulate approximately $101,597 after 10 years of consistent investing.
That same investor would see their portfolio grow to around $396,902 after 20 years, crossing the $1 million threshold somewhere around the 28-year mark.
While no investment is guaranteed, the mathematics of consistent monthly contributions combined with compounding returns over decades make a powerful argument for staying invested in broadly diversified index funds.
SPYM may lack the name recognition of the popular State Street SPY fund or the massive asset base of the Vanguard S&P 500 ETF, but its ultra-low expense ratio and strong long-term performance make it genuinely competitive.
For investors who missed earlier opportunities in individual stocks, broad market index funds like SPYM offer a time-tested path to building substantial long-term wealth without requiring active stock-picking decisions.
