ETF comparison
IWR vs MDY
Both US Mid Cap.
iShares Russell Mid-Cap ETF · State Street SPDR S&P MIDCAP 400 ETF Trust
Holdings overlap
307 positions appear in both funds. Buying equal dollars of IWR and MDY would leave roughly 21.7% of each dollar exposed to the same underlying securities.
Unmatched is the part of a fund's weight the other fund doesn't match: names only it holds, plus any extra weight it puts in names both funds hold.
Side by side
Sub-score comparison
Tracking quality isn't part of the composite — see what we don't score for why.
Cost difference
IWR is 5 bps cheaper than MDY. On a $100,000 position that's about $50/yr more in fees for MDY.
Fee figure is the annual expense charged on $100,000. To see how the gap compounds over a multi-decade holding period, open the cost calculator pre-filled with IWR vs MDY.
Top shared holdings
307 shared in total| # | Holding | In IWR | In MDY | Overlap |
|---|---|---|---|---|
| 1 | Twilio, Inc. | 0.22% | 1.30% | 0.22% |
| 2 | MKS, Inc. | 0.22% | 0.54% | 0.22% |
| 3 | Carpenter Technology Corp. | 0.22% | 0.55% | 0.22% |
| 4 | Curtiss-Wright Corp. | 0.20% | 0.58% | 0.20% |
| 5 | Entegris, Inc. | 0.20% | 0.73% | 0.20% |
| 6 | ATI, Inc. | 0.19% | 0.75% | 0.19% |
| 7 | MasTec, Inc. | 0.19% | 0.39% | 0.19% |
| 8 | MACOM Technology Solutions Holdings, Inc. | 0.18% | 0.64% | 0.18% |
| 9 | Woodward, Inc. | 0.18% | 0.56% | 0.18% |
| 10 | Sterling Infrastructure, Inc. | 0.18% | 0.47% | 0.18% |
| 11 | XPO, Inc. | 0.17% | 0.62% | 0.17% |
| 12 | Okta, Inc. | 0.17% | 1.01% | 0.17% |
Only in IWR
517 total- Datadog, Inc. 0.62%
- Snowflake, Inc. 0.61%
- Royal Caribbean Cruises Ltd. 0.58%
- Cloudflare, Inc. 0.56%
- Robinhood Markets, Inc. 0.56%
- Teradyne, Inc. 0.55%
- Marathon Petroleum Corp. 0.54%
- Astera Labs, Inc. 0.53%
- Simon Property Group, Inc. 0.52%
- United Rentals, Inc. 0.51%
Only in MDY
94 total- U.S. Dollar 0.89%
- nVent Electric plc 0.79%
- TechnipFMC plc 0.77%
- Roivant Sciences Ltd. 0.55%
- Fabrinet 0.48%
- Jazz Pharmaceuticals Public Limited Company 0.44%
- SharkNinja Inc. 0.44%
- RenaissanceRe Holdings Ltd. 0.39%
- CNH Industrial NV 0.33%
- Moog Inc. Class A 0.32%
Related comparisons
More comparisons with IWR
- IWR vs VTV · Vanguard Morningstar Value ETF 19.9%
- IWR vs VTI · Vanguard Morningstar Total Stock Market ETF 18.8%
- IWR vs ITOT · iShares Core S&P Total U.S. Stock Market ETF 18.7%
- IWR vs SCHB · Schwab U.S. Broad Market ETF 18.3%
- IWR vs DGRO · iShares Core Dividend Growth ETF 17.3%
- IWR vs IJK · iShares S&P Mid-Cap 400 Growth ETF 15.9%
More comparisons with MDY
- MDY vs IWP · iShares Russell Mid-Cap Growth ETF 17.3%
- MDY vs IWM · iShares Russell 2000 ETF 11.0%
- MDY vs IWD · iShares Russell 1000 Value ETF 6.8%
- MDY vs VTI · Vanguard Morningstar Total Stock Market ETF 5.0%
- MDY vs ITOT · iShares Core S&P Total U.S. Stock Market ETF 4.8%
- MDY vs SCHB · Schwab U.S. Broad Market ETF 4.6%
Percentages are holdings overlap with the named fund.
Open IWR or MDY at a brokerage
Both funds trade commission-free at major US brokerages.
Affiliate links — opening an account through these earns PlainIndex a one-time referral. Scoring is computed before any affiliate consideration; see our methodology and funding disclosure.
Holdings overlap is the sum of min(weight_a, weight_b) over positions
matched on ISIN (CUSIP fallback). Methodology: see
/methodology/.
Comparing two funds doesn't endorse swapping one for the other. Tax-lot history, account type, and personal goals matter — PlainIndex publishes data and methodology, not investment advice.