IWO spreads its bets; MGK concentrates them
Key Points
iShares Russell 2000 Growth ETF offers exposure to over 1,000 small-cap stocks while Vanguard Mega Cap Growth ETF focuses on 69 of the largest U.S. growth companies
Vanguard Mega Cap Growth ETF is the more cost-effective choice with an expense ratio of 0.05% versus 0.24% for iShares Russell 2000 Growth ETF
iShares Russell 2000 Growth ETF delivered a higher 1-year total return of 43% but experienced a larger maximum drawdown of 40.50% over the last five years
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iShares Russell 2000 Growth ETF (NYSEMKT:IWO) targets small-cap volatility and high upside, whereas Vanguard Mega Cap Growth ETF (NYSEMKT:MGK) provides lower-cost exposure to the established giants of the U.S. economy.
These two funds offer distinct ways to capture growth across the market-cap spectrum. One looks at the "big fish" in the technology and communication sectors, while the other scours the small-cap universe for emerging companies with higher potential volatility. Choosing between them requires weighing the low-cost efficiency of mega-caps against the diversification and upside of smaller firms.
Snapshot (cost & size)
| Metric | MGK | IWO |
|---|---|---|
| Issuer | Vanguard | iShares |
| Expense ratio | 0.05% | 0.24% |
| 1-yr return (as of May 6, 2026) | 36.11% | 43.09% |
| Dividend yield | 0.33% | 0.41% |
| Beta | 1.23 | 1.20 |
| AUM | $31.89 billion | $14.57 billion |
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.
Performance & risk comparison
| Metric | MGK | IWO |
|---|---|---|
| Max drawdown (5 yr) | (36.00%) | (40.50%) |
| Growth of $1,000 over 5 years (total return) | $2,029 | $1,294 |
What's inside
The iShares Russell 2000 Growth ETF (NYSEMKT:IWO) provides exposure to 1,093 small-capitalization stocks that exhibit growth characteristics. Its sector allocation is led by healthcare at 25.00%, technology at 22.00%, and industrials at 21.00%. Its largest positions include Bloom Energy Corp. (NYSE:BE) at 3.71%, Credo Technology Group Holding Ltd. (NASDAQ:CRDO) at 1.79%, and Sterling Infrastructure Inc. (NASDAQ:STRL) at 1.38%. It was launched in 2000 and has a trailing-12-month dividend of $1.51 per share.
The Vanguard Mega Cap Growth ETF (NYSEMKT:MGK) tracks 69 of the largest growth stocks in the U.S. and employs a passively managed, full-replication approach. Its portfolio is heavily tilted toward technology at 55.00%, communication services at 17.00%, and consumer cyclical at 13.00%. Its largest positions include Nvidia Corp. (NASDAQ:NVDA) at 13.73%, Apple Inc. (NASDAQ:AAPL) at 12.58%, and Microsoft Corp. (NASDAQ:MSFT) at 9.00%. Launched in 2007, it has a trailing-12-month dividend of $1.18 per share.
What this means for investors
The Vanguard fund's name suggests broad mega-cap exposure, but the math tells a different story. Nvidia, Apple, and Microsoft alone make up over 35% of the portfolio, and 72% of holdings sit in tech and communication services. That's not diversification — it's a concentrated bet on a few trillion-dollar names. The iShares fund's 1,093-holding spread across healthcare, tech, and industrials is genuinely diversified by comparison, with no position above 4%. Yet despite being marketed as opposite ends of the risk spectrum, the funds' betas are nearly identical at 1.23 and 1.20. The small-cap fund isn't meaningfully more volatile than the mega-cap one. The intuition that "small caps are riskier" doesn't really apply here — both move with the market at similar magnitudes. So the choice isn't really about risk tolerance. It's about what kind of growth bet you want: a few proven giants or a wide net of unproven smaller companies. Cost favors Vanguard, but cheaper doesn't mean safer.
For more guidance on ETF investing, check out the full guide at this link.
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Seena Hassouna has positions in Apple and Nvidia. The Motley Fool has positions in and recommends Apple, Bloom Energy, Microsoft, Nvidia, and Sterling Infrastructure. The Motley Fool has a disclosure policy.
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