Which Is the Better ETF, Vanguard's Mega-Cap MGK or iShares' Small-Cap IWO?

By Robert Izquierdo – Apr 18, 2026 at 10:35AM ESTKey PointsIWO takes on higher fees but delivered a stronger 1-year return and slightly higher yield.MGK focuses on mega-cap tech and communications, while IWO spreads across 1,100+ small-cap growth names with a tilt to healthcare and industrials.Risk is higher for IWO, with a steeper max drawdown and much lower five-year growth of $1,000.The Vanguard Mega Cap Growth ETF (MGK +1.44%) and iShares Russell 2000 Growth ETF (IWO +2.20%) differ sharply on cost, sector exposure, and risk profile, with MGK targeting the largest U.S. growth stocks and IWO offering access to a sprawling basket of small-cap growth companies.Both funds aim to capture U.S. growth equities, but their approaches and underlying portfolios are worlds apart. This comparison lays out how MGK’s mega-cap tech concentration stacks up against IWO’s broad small-cap exposure, helping investors weigh cost, performance, diversification, and volatility.Snapshot (cost & size)MetricMGKIWOIssuerVanguardISharesExpense ratio0.05%0.24%1-yr return (as of 2026-04-16)40.8%46.5%Dividend yield0.4%0.5%Beta1.171.46AUM$27.9 billion$12.2 billionBeta 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.MGK is meaningfully more affordable, with a 0.05% expense ratio versus IWO’s 0.24%. IWO edges out MGK on dividend yield, offering a 0.5% payout compared to MGK’s 0.4%.Performance & risk comparisonMetricMGKIWOMax drawdown (5 y)-36.02%-40.51%Growth of $1,000 over 5 years$1,895$1,198What's insideIWO tracks a small-cap growth universe, holding over 1,100 names and spreading assets primarily across healthcare (25%), technology (22%), and industrials (21%). Its largest positions, such as Bloom Energy Class A (BE 1.39%), Credo Technology Group (CRDO +1.11%), and Fabrinet (FN +2.56%), each account for less than 3% of assets, reflecting deep diversification. The fund has a long track record at 25.7 years.MGK, in contrast, is a concentrated play on the U.S. mega-cap growth space, with technology, communication services, and consumer cyclical stocks dominating the portfolio. Its top holdings — Nvidia (NVDA +1.67%), Apple (AAPL +2.65%), and Microsoft (MSFT +0.60%) — make up a far larger portion of assets, highlighting a heavy tilt toward the largest tech names.For more guidance on ETF investing, check out the full guide at this link.What this means for investorsChoosing between the Vanguard Mega Cap Growth ETF (MGK) and iShares Russell 2000 Growth ETF (IWO) comes down to individual investor strategies and goals. MGK grants exposure to the biggest companies in the U.S. stock market while IWO focuses on the smallest.MGK is for those who want to invest in giants such as Nvidia and Microsoft. As a result, the ETF offers more stability and reduced risk. This is illustrated in MGK’s lower beta and max drawdown over the last five years. Other advantages include MGK’s low expense ratio of 0.05% and larger AUM of nearly $30 billion, which offers greater liquidity for those interested in more active trading.IWO is for investors seeking high-growth companies that can deliver explosive returns. Small-scale enterprises can more easily achieve substantial year-over-year revenue gains compared to behemoths like Apple, since many are growing their businesses, while established companies may require a significant secular trend, such as artificial intelligence, to drive up growth rates.Moreover, while the fund is far more costly with an expense ratio of 0.24%, you get greater diversification thanks to the more than 1,000 stocks the ETF holds. However, the downside is that smaller businesses can experience higher volatility, which contributes to IWO’s larger beta and max drawdown.For investors who want a long-term, stable ETF, MGK is for you. IWO is for those who desire the potential for big returns, and are willing to experience greater risk, volatility, and costs in exchange.Read NextApr 17, 2026 •By Sara AppinoQQQ vs. IWO: Big Tech Dominance or Small-Cap Potential?Mar 27, 2026 •By Josh Kohn-LindquistVanguard (VONG) vs. iShares (IWO): Which Growth Stock ETF Is Best for Investors?Mar 26, 2026 •By Katie BrockmanIWO vs. VOOG: How Small-Cap Diversification Compares to Large-Cap GrowthMar 26, 2026 •By Jake LerchIWO vs. VUG: One Offers Broad Growth Exposure While the Other Has Lower FeesMar 25, 2026 •By Katie BrockmanIWO vs. MGK: Is Small-Cap Growth or Mega-Cap Tech the Better Choice for Investors?Apr 18, 2026 •By Robert IzquierdoBetter iShares International ETF: IEFA vs. IEMGAbout the AuthorRobert "Izzy" Izquierdo is a contributing Motley Fool stock market analyst covering information technology, consumer discretionary, consumer staples, and communication services sectors. Prior to The Motley Fool, Izzy was head of product management at Target Media Partners, developing and launching multimillion-dollar software used by businesses such as Charter Communications. Prior to that, he worked at Yahoo! and startups on software products in connected TV, AI, consumer apps, and digital advertising. He holds a bachelor’s degree in English literature from UCLA and is certified in software product management.TMFWryWriteStocks MentionediShares Trust - iShares Russell 2000 Growth ETFNYSEMKT: IWO$356.35(+2.20%)+$7.68Vanguard World Fund - Vanguard Mega Cap Growth ETFNYSEMKT: MGK$415.92(+1.44%)+$5.89*Average returns of all recommendations since inception. Cost basis and return based on previous market day close.