IWS vs SPY: Holdings Overlap
IWSiShares Russell Mid-Cap Value ETF
iShares · 712 holdings · $15.9B · as of 2026-03-31
SPYState Street® SPDR® S&P 500® ETF Trust
State Street (SPDR) · 504 holdings · $812.0B · as of 2026-08-06
Holdings snapshots are 128 days apart (IWS: 2026-03-31, SPY: 2026-08-06). Weights and index membership change between snapshots, so the true current overlap is typically higher than shown. For funds tracking the same index, the gap can be 5–15 points.
How similar are IWS and SPY?
iShares Russell Mid-Cap Value ETF (IWS, by iShares) holds 712 positions; State Street® SPDR® S&P 500® ETF Trust (SPY, by State Street (SPDR)) holds 504. They have 272 holdings in common, and by portfolio weight the two funds are 12.5% identical. In practical terms the pair is lightly overlapping, with most of each portfolio distinct.
- Overlap by Weight
- 12.5%Sum of the smaller weight of each shared holding
- Shared Holdings
- 272IWS holds 712 · SPY holds 504
- Weight in Shared Holdings
- IWS 68%·SPY 13%Share of each fund's weight in stocks both funds own
Based on each fund's latest official holdings. How is this calculated?
What makes each fund different
Only in IWS
440 of 712 positions (31.3% of the fund) are not held by SPY. Showing the top 30 by weight.
Sector Breakdown
| Sector | IWS | SPY |
|---|---|---|
| Information Technology | 12.3% | 37.6% |
| Industrials | 17.1% | 8.8% |
| Financials | 15.1% | 12.3% |
| Communication Services | 3.2% | 9.7% |
| Consumer Discretionary | 7.8% | 9.3% |
| Other Sectors | 44.0% | 22.3% |
Share of each fund's portfolio weight by GICS-style sector, compiled from issuer fund data and our own classification of the holdings, not the issuers' published sector charts.
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| IWS | +3.3% | +22.1% | +29.8% | +16.6% | +9.8% | +10.4% | 1.27% |
| SPY | +3.4% | +14.0% | +23.7% | +21.2% | +13.3% | +15.3% | 0.97% |
Total returns including dividends, from adjusted daily closes as of 2026-08-07. 3Y/5Y/10Y are annualized. Yield is trailing-12-month distributions over the last close. Past performance does not predict future results.
Project the growth of $10,000 in IWS vs SPY →
Shared Holdings(272)
The top 10 shared positions account for 13% of the overlap, led by SNDK, WDC and GLW.
 SNDKSandisk Corporation COM | 0.92% | 0.28% | 0.28% |
|---|---|---|---|
 WDCWestern Digital Corp. COM | 0.94% | 0.23% | 0.23% |
 GLWCorning Incorporated COM | 1.08% | 0.19% | 0.19% |
 BNYThe Bank of New York Mellon Corp. COM | 0.77% | 0.16% | 0.16% |
 PWRQuanta Services, Inc. COM | 0.19% | 0.15% | 0.15% |
 VLOValero Energy Corp. COM | 0.76% | 0.14% | 0.14% |
 CMICummins Inc. COM | 0.75% | 0.13% | 0.13% |
 MPCMarathon Petroleum Corp. COM | 0.75% | 0.13% | 0.13% |
 PSXPhillips 66 COM | 0.69% | 0.12% | 0.12% |
 ROSTRoss Stores Inc COM | 0.56% | 0.12% | 0.12% |
 URIUnited Rentals, Inc. COM | 0.47% | 0.11% | 0.11% |
 SPGSimon Property Group Inc COM | 0.48% | 0.11% | 0.11% |
 HOODRobinhood Markets, Inc., Class A | 0.46% | 0.11% | 0.11% |
 ALLThe Allstate Corporation COM | 0.55% | 0.11% | 0.11% |
 HPEHewlett Packard Enterprise Co. COM | 0.32% | 0.10% | 0.10% |
 DLRDigital Realty Trust Inc. COM | 0.63% | 0.10% | 0.10% |
 WBDWarner Bros. Discovery Inc. COM SER A | 0.65% | 0.10% | 0.10% |
 COHRCoherent Corp COM | 0.42% | 0.10% | 0.10% |
 LITELumentum Holdings Inc. COM | 0.47% | 0.10% | 0.10% |
 BKRBaker Hughes Company CL A | 0.62% | 0.09% | 0.09% |
 NUENucor Corporation COM | 0.40% | 0.09% | 0.09% |
 KMIKinder Morgan, Inc. COM | 0.66% | 0.09% | 0.09% |
 TERTeradyne Inc. COM | 0.47% | 0.09% | 0.09% |
 DALDelta Air Lines Inc. COM NEW | 0.44% | 0.09% | 0.09% |
 FASTFastenal Co. COM | 0.10% | 0.09% | 0.09% |
Showing the top 250 of 272 shared holdings by overlap weight.
Frequently Asked Questions
How much do IWS and SPY overlap?
IWS and SPY overlap by 12.5% of portfolio weight. They share 272 holdings (IWS holds 712 positions and SPY holds 504), based on each fund's latest SEC-reported holdings.
Is it redundant to own both IWS and SPY?
The two portfolios are 12.5% identical by weight. Owning both is not redundant. Most of each portfolio is distinct, so the funds can serve different roles.
What are the biggest shared holdings of IWS and SPY?
The largest positions held by both funds are SNDK, WDC, GLW, BNY and PWR. Together the top 10 shared positions account for 13% of the total overlap.
What does IWS own that SPY doesn't?
440 positions (31.3% of IWS) are unique to IWS, led by EA, AU and LNG. In the other direction, 232 positions (87.3% of SPY) are unique to SPY.