ETF comparison
IWS vs SPY
US Mid Cap vs US Large Cap.
iShares Russell Mid-Cap Value ETF · State Street SPDR S&P 500 ETF Trust
Holdings overlap
257 positions appear in both funds. Buying equal dollars of IWS and SPY would leave roughly 11.1% 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 14 bps cheaper than IWS. On a $100,000 position that's about $136/yr more in fees for IWS.
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 IWS vs SPY.
Top shared holdings
257 shared in total| # | Holding | In IWS | In SPY | Overlap |
|---|---|---|---|---|
| 1 | MARATHON PETROLEUM CORP | 0.36% | 0.17% | 0.17% |
| 2 | PHILLIPS 66 | 0.62% | 0.16% | 0.16% |
| 3 | MODERNA INC | 0.25% | 0.14% | 0.14% |
| 4 | UNITED RENTALS INC | 0.53% | 0.11% | 0.11% |
| 5 | ROBINHOOD MARKETS INC | 0.13% | 0.10% | 0.10% |
| 6 | ALLSTATE CORP (THE) | 0.60% | 0.10% | 0.10% |
| 7 | KIMBERLY CLARK CORP | 0.24% | 0.10% | 0.10% |
| 8 | HEWLETT PACKARD ENTERPRISE COMPANY | 0.59% | 0.10% | 0.10% |
| 9 | DIGITAL REALTY TRUST INC | 0.62% | 0.10% | 0.10% |
| 10 | KINDER MORGAN INC | 0.61% | 0.09% | 0.09% |
| 11 | FASTENAL COMPANY | 0.10% | 0.09% | 0.09% |
| 12 | CARDINAL HEALTH INC | 0.30% | 0.09% | 0.09% |
Only in IWS
463 total- WARNER BROS. DISCOVERY INC 0.63%
- FLEX LTD 0.58%
- CORTEVA INC 0.56%
- ONEOK INC 0.54%
- CHENIERE ENERGY INC 0.46%
- ELECTRONIC ARTS INC 0.43%
- GARMIN LTD 0.38%
- CARNIVAL CORP LTD 0.36%
- KENVUE INC 0.35%
- ROYAL CARIBBEAN CRUISES LTD 0.34%
Only in SPY
247 total- APPLE INC 7.69%
- NVIDIA CORP 7.30%
- MICROSOFT CORP 6.22%
- AMAZON.COM INC 3.94%
- ALPHABET INC CL A 2.56%
- BROADCOM INC 2.33%
- META PLATFORMS INC CLASS A 2.09%
- ALPHABET INC CL C 2.06%
- ELI LILLY + CO 1.71%
- TESLA INC 1.64%
Related comparisons
More comparisons with IWS
More comparisons with SPY
- SPY vs NOBL · ProShares S&P 500 Dividend Aristocrats ETF 10.8%
- SPY vs HDV · iShares Core High Dividend ETF 10.3%
- SPY vs RPV · Invesco S&P 500 Pure Value ETF 9.9%
- SPY vs VOE · Vanguard Morningstar Mid-Cap Value ETF 9.9%
- SPY vs DVY · iShares Select Dividend ETF 8.7%
- SPY vs SCHD · Schwab U.S. Dividend Equity ETF 8.2%
Percentages are holdings overlap with the named fund.
Open IWS 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.