IWO vs. SPY: Small-Cap Growth Potential Against Large-Cap Stability

iShares Russell 2000 Growth ETF (IWO +0.66%) targets small-cap companies with rapid growth potential, whereas State Street SPDR S&P 500 ETF Trust (SPY +0.80%) offers a diversified anchor of the largest U.S. corporations.

Investors may choose between the broad-market stability of the S&P 500 and the higher risk-reward potential of small-cap growth equities. The State Street SPDR S&P 500 ETF Trust serves as the global standard for large-cap domestic equity, while the iShares Russell 2000 Growth ETF filters smaller companies for aggressive expansion traits.

Snapshot (cost & size)

Beta measures price volatility relative to the S&P 500; beta is calculated from five-year monthly returns. The 1-yr return represents total return over the trailing 12 months. Dividend yield is the trailing-12-month distribution yield.

The iShares Russell 2000 Growth ETF is more expensive to hold with a 0.24% expense ratio compared to 0.09% for the SPDR trust. Additionally, the SPDR trust provides a higher payout, offering a 1.00% yield versus 0.40% for the iShares fund.

Performance & risk comparison

What’s inside

The iShares Russell 2000 Growth ETF (IWO) focuses on small-cap growth, with primary sector allocations to Healthcare 25%, Technology 22%, and Industrials 21%. It holds 1,093 companies, and its largest positions include Bloom Energy (BE +1.22%) at 3.71%, Credo Technology Group Holding (CRDO +0.11%) at 1.79%, and Sterling Infrastructure (STRL +4.06%) at 1.38%. The fund was launched in 2000 and has a trailing-12-month dividend of $1.51 per share.

In contrast, the State Street SPDR S&P 500 ETF Trust (SPY) tracks large-cap benchmarks, tilting heavily toward Technology 34%, Financial Services 12%, and Communication Services 10%. Its top holdings include Nvidia (NVDA +1.73%) at 8.00%, Apple (AAPL +2.08%) at 6.68%, and Microsoft (MSFT 1.33%) at 4.87%. It manages 505 holdings, was launched in 1993, and paid $7.38 per share over the trailing 12 months.

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What this means for investors

SPY and IWO occupy opposite ends of the U.S. equity universe, and putting them side by side makes the contrast vivid. SPY is the original U.S. ETF, tracking the S&P 500’s 500 largest companies with nearly $685 billion in assets, making this a bedrock holding for millions of investors worldwide. IWO targets the riskiest, fastest-growing corner of the market: small-cap growth companies with high valuations, minimal profitability requirements, and significant room to either soar or stumble.

The sector profiles couldn’t be more different. SPY leans heavily into megacap technology. IWO spreads across healthcare, industrials, and technology in roughly equal measure, with no single holding carrying meaningful weight and no company anywhere near the scale of an Apple or Nvidia.

SPY charges less than a third of what IWO does, and its long-term track record is hard to argue with. IWO suits investors who want to tilt aggressively toward small-cap growth and accept significantly more volatility in pursuit of higher long-term returns. For most portfolios, SPY is the foundation; IWO is the high-conviction satellite.