ETF comparison
IWR vs SPY
US Mid Cap vs US Large Cap.
iShares Russell Mid-Cap ETF · State Street SPDR S&P 500 ETF Trust
Holdings overlap
287 positions appear in both funds. Buying equal dollars of IWR and SPY would leave roughly 12.1% 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
SPY is 9 bps cheaper than IWR. On a $100,000 position that's about $86/yr more in fees for IWR.
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 SPY.
Top shared holdings
287 shared in total| # | Holding | In IWR | In SPY | Overlap |
|---|---|---|---|---|
| 1 | Marathon Petroleum Corp. | 0.54% | 0.18% | 0.18% |
| 2 | Phillips 66 | 0.49% | 0.16% | 0.16% |
| 3 | Lumentum Holdings, Inc. | 0.44% | 0.14% | 0.14% |
| 4 | Datadog, Inc. | 0.62% | 0.14% | 0.14% |
| 5 | Hewlett Packard Enterprise Co. | 0.43% | 0.14% | 0.14% |
| 6 | Robinhood Markets, Inc. | 0.56% | 0.13% | 0.13% |
| 7 | Warner Bros Discovery, Inc. | 0.46% | 0.12% | 0.12% |
| 8 | Moderna, Inc. | 0.18% | 0.11% | 0.11% |
| 9 | Teradyne, Inc. | 0.55% | 0.11% | 0.11% |
| 10 | United Rentals, Inc. | 0.51% | 0.10% | 0.10% |
| 11 | Coherent Corp. | 0.50% | 0.10% | 0.10% |
| 12 | Keysight Technologies, Inc. | 0.43% | 0.10% | 0.10% |
Only in IWR
537 total- Snowflake, Inc. 0.61%
- Royal Caribbean Cruises Ltd. 0.58%
- Cloudflare, Inc. 0.56%
- Astera Labs, Inc. 0.53%
- Flex Ltd. 0.43%
- ONEOK, Inc. 0.40%
- Rocket Lab Corp. 0.39%
- Electronic Arts, Inc. 0.37%
- Cheniere Energy, Inc. 0.36%
- Credo Technology Group Holding Ltd. 0.32%
Only in SPY
218 total- NVIDIA CORP 8.50%
- APPLE INC 7.32%
- MICROSOFT CORP 5.77%
- AMAZON.COM INC 3.71%
- ALPHABET INC CL A 3.03%
- BROADCOM INC 2.54%
- ALPHABET INC CL C 2.43%
- META PLATFORMS INC CLASS A 2.41%
- MICRON TECHNOLOGY INC 1.82%
- TESLA INC 1.57%
Related comparisons
More comparisons with IWR
More comparisons with SPY
- SPY vs SDY · State Street SPDR S&P Dividend ETF 11.8%
- SPY vs IWS · iShares Russell Mid-Cap Value ETF 10.4%
- SPY vs RPV · Invesco S&P 500 Pure Value ETF 9.5%
- SPY vs VOE · Vanguard Morningstar Mid-Cap Value ETF 9.3%
- SPY vs HDV · iShares Core High Dividend ETF 9.2%
- SPY vs NOBL · ProShares S&P 500 Dividend Aristocrats ETF 8.8%
Percentages are holdings overlap with the named fund.
Open IWR or SPY 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.