Generated July 2026 from current fund data.
Overview
SPY and VOO are nearly identical large-cap index funds that track the S&P 500 before expenses. Both hold the same 500 stocks and charge minimal fees, but they differ in cost structure and dividend yield. SPY is older and larger in some respects, while VOO has become the larger fund overall and offers a lower expense ratio.
How they differ
The critical difference is expense ratio: VOO charges 0.03% while SPY charges 0.10%—a 70% cost advantage that compounds over decades. On a $100,000 position, that's $70 per year in extra costs for SPY. VOO also distributes a slightly higher yield (1.13% vs. 1.01%), which may reflect Vanguard's structural efficiency or timing of dividend reinvestment. Size-wise, VOO has surpassed SPY in AUM ($1033B vs. $783B), though both are enormous and highly liquid. SPY predates VOO by 17 years, giving it longer track record, but that historical edge is largely irrelevant since both simply replicate the same index.
Who each is best for
SPY: Fits investors with deep familiarity with State Street's ETF ecosystem or those already holding SPY in legacy accounts where switching costs outweigh the fee savings.
VOO: Fits cost-conscious index investors who are building a new S&P 500 position and prioritize the lowest expense drag, especially those planning to hold for decades.
Key risks to know
- Index concentration: Both funds are heavily weighted to the largest mega-cap technology and financial stocks, meaning they move in lockstep with that subset of the market. A prolonged underperformance of mega-cap growth would affect both equally.
- Market-cap weighting drag: Both use market-cap weighting, which mechanically forces each fund to buy high (concentrating into winners) and sell low (trimming losers). This is not a flaw in either fund's construction, but it's a structural headwind versus equal-weight or value-tilted alternatives.
- Domestic equity-only exposure: Both funds exclude international developed and emerging markets, leaving currency and geopolitical risk unhedged. A sustained dollar rally or U.S. relative underperformance would hurt both identically.
Bottom line
If you prioritize the absolute lowest costs and are opening a new position, VOO's 0.03% expense ratio and slightly higher yield offer a measurable edge over SPY's 0.10%. If you already own SPY and the switch would trigger taxes or trading costs, that gap probably isn't worth acting on. Both track the same index with the same beta, so the choice hinges on expense discipline, not on which will outperform. Past performance doesn't predict future results.
AI-generated analysis for educational purposes only. Verify important details independently; past performance does not guarantee future results.
