IWR vs MMID
iShares Russell Mid-Cap ETF vs MFS Active Mid Cap ETF
Which is better, IWR or MMID?
IWR has been ahead.
IWR has a lower expense ratio. IWR led over 1Y and the full window. IWR is less concentrated, with 7.0% of the fund in its ten largest positions against 16.2%.
MarketXLS is not an investment adviser. This comparison is generated automatically from market data and is for information only. A Best mark means the better reading on that one measure, not a recommendation to buy.
Side-by-Side Comparison
| Metric | IWR | MMID |
|---|---|---|
| Expense Ratio | 0.18%Best | 0.59% |
| AUM | $56.7B | $36M |
| Dividend Yield | 1.19% | 0.99% |
| Holdings | 825 | 106 |
| YTD Return | +12.13%Best | +5.51% |
| 1Y Return | +14.18%Best | +6.40% |
| 3Y Return (annualized) | +17.55% | - |
| 5Y Return (annualized) | +7.30% | - |
| Volatility (annualized) | 11.6% | 10.5%Best |
| Max Drawdown | -8.2% | -7.9%Best |
| $10,000 over 1.1 years | $11,492Best | $10,724 |
| Top 10 Weight | 7.0%Best | 16.2% |
| Fund Family | iShares by BlackRock (US) | MFS Investment Management |
| Category | Equity | Equity |
| Style | Mid Cap Blend | Mid Cap Blend |
| Inception | Jul 17, 2001 | Sep 24, 2025 |
Volatility and max drawdown, and the $10,000 over 1.1 years row, are measured over the window both funds cover: Sep 24, 2025 to Oct 14, 2026 (1.1 years).
IWR vs MMID growth
Month-end closes. Both lines start at 0% in the first month shown, so the gap between them is the difference in growth across that window. The full view covers the 1.1 years both funds cover.
IWR vs MMID Performance
iShares Russell Mid-Cap ETF (IWR) is an ETF from iShares by BlackRock (US) and MFS Active Mid Cap ETF (MMID) is an ETF from MFS Investment Management. Over the past year IWR returned +14.18% while MMID returned +6.40%. Year to date, IWR is up 12.13% versus a gain of 5.51% for MMID.
Past performance does not guarantee future results.
Risk: Volatility and Drawdowns
IWR has been the more volatile fund, with annualized monthly volatility of 11.6% compared with 10.5% for MMID. Lower volatility generally means a smoother ride, though it often comes with lower long-run returns.
The deepest peak-to-trough decline in our data was -8.2% for IWR and -7.9% for MMID. Drawdown depth is what each fund did in the worst stretch of the window measured above.
The two funds' monthly returns correlate at 0.88. They usually move together, but the gap leaves some room for diversification.
Fees and Cost Over Time
IWR charges 0.18% per year while MMID charges 0.59%. On a $10,000 position that is $18 vs $59 annually, a gap of $41 per year that compounds over a long holding period. On income, IWR currently yields 1.19% against 0.99% for MMID.
Holdings Overlap
14.5% of IWR's money is in holdings MMID also owns. 87.0% of MMID's money is in holdings IWR also owns.
Most of MMID is already inside IWR. Owning both mostly buys the same companies twice.
89 positions in common, counted across the 823 positions we hold weights for in IWR and 104 in MMID, against full books of 825 and 106.
What only one of them owns
Our book lists 10 positions for MMID that do not appear in our book for IWR (8.3% of the fund), and 706 for IWR that do not appear in MMID (82.9%).
Some of those will be the same company recorded under a different code in one of the two books, so the real difference in what you would own is no larger than this and may be smaller. We do not name the individual positions here for that reason.
Top Shared Holdings
| Stock | Weight in IWR | Weight in MMID | Difference |
|---|---|---|---|
| SNOWSnowflake Inc | 0.85% | 1.32% | 0.47% |
| LNGCheniere Energy Inc. | 0.42% | 1.70% | 1.28% |
| WATWaters Corp. | 0.31% | 1.78% | 1.47% |
| AAgilent Technologies Inc | 0.35% | 1.69% | 1.34% |
| BDXBecton Dickinson And Co. | 0.36% | 1.64% | 1.28% |
| HPEHewlett Packard Enterprise Co | 0.64% | 1.36% | 0.72% |
| GPNGlobalpayments Inc. | 0.14% | 1.86% | 1.72% |
| FANGDiamondback Energy Inc - Common | 0.28% | 1.61% | 1.33% |
| GWWWw Grainger Inc. | 0.41% | 1.45% | 1.04% |
| WABWestinghouse Air Brake Technologies Corp. | 0.36% | 1.48% | 1.12% |
87.0% of MMID is already inside IWR.
You probably hold more than these two. Add the rest and see how much of the whole book is the same companies twice.
Free for up to 10 holdings. No account needed.
Frequently Asked Questions
Which is cheaper, IWR or MMID?
IWR has an expense ratio of 0.18% while MMID charges 0.59%. IWR is the cheaper option, by $41 a year on a $10,000 investment.
Which performed better, IWR or MMID?
Over the past year IWR returned +14.18% vs +6.40% for MMID, so IWR leads on 1-year performance. Over the longest common window we track (1 years), IWR annualized +13.48% vs +6.56% for MMID. Past performance does not guarantee future results. This is information, not a recommendation.
Which is riskier, IWR or MMID?
IWR has been the more volatile fund at 11.6% annualized versus 10.5% for MMID. Worst drawdown: IWR -8.2% vs MMID -7.9%.
Should I hold both IWR and MMID?
IWR and MMID have a monthly-return correlation of 0.88, so their returns are far enough apart for the mix to behave differently from either one alone. This is information, not a recommendation.
What is the holdings overlap between IWR and MMID?
87.0% of MMID's money is in holdings IWR also owns. 87.0% of MMID's is in holdings IWR also owns. They hold 89 positions in common, counted across the 823 positions we hold weights for in IWR and 104 in MMID.
Which pays a higher dividend, IWR or MMID?
IWR yields 1.19% while MMID yields 0.99%, so IWR currently pays the higher dividend yield.
Is MMID better than IWR?
IWR has a lower expense ratio. IWR led over 1Y and the full window. IWR is less concentrated, with 7.0% of the fund in its ten largest positions against 16.2%. Which one suits a particular account depends on what it is for. This is information, not a recommendation.