Since its inception, the SPDR S&P 500 ETF Trust has delivered an average annual return of roughly 10%, translating into a doubling of invested capital approximately every seven years. On a hypothetical $1,000 investment, compounding at that rate would grow the balance to about $5,560 after 18 years and nearly $490,000 after 65 years. These figures highlight the powerful effect of long-term compounding when tracking the broad U.S. large-cap market through SPY.

SPY’s expense ratio of 0.08% stands among the lowest in the ETF universe, meaning annual fees on a $10,000 position amount to just $8. Over multi-decade time horizons, that cost differential can add up to tens of thousands of dollars compared with higher-cost vehicles. By minimizing drag from fees, SPY allows investors to capture a larger share of the underlying index’s performance.

With average daily trading volume exceeding 70 million shares, SPY remains the most heavily traded ETF in the world. This depth ensures ultra-tight bid-ask spreads—often just a fraction of a cent per share—which benefits active traders and institutions executing large orders. High liquidity also reduces market impact, allowing investors to enter and exit positions with minimal slippage.

For long-term investors, SPY serves as a core building block that provides broad diversification across 500 leading U.S. companies. Its simple, transparent structure and consistent tracking of the S&P 500 make it an ideal choice for retirement accounts, education savings plans, and taxable portfolios. Regular contributions to SPY can harness dollar-cost averaging and compound growth to build substantial wealth over decades.