ITOT vs MDY: Holdings Overlap
ITOTiShares Core S&P Total U.S. Stock Market ETF
iShares · 2487 holdings · $97.6B · as of 2026-03-31
MDYState Street® SPDR® S&P MIDCAP 400® ETF Trust
State Street (SPDR) · 399 holdings · $27.1B · as of 2026-08-06
Holdings snapshots are 128 days apart (ITOT: 2026-03-31, MDY: 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 ITOT and MDY?
iShares Core S&P Total U.S. Stock Market ETF (ITOT, by iShares) holds 2487 positions; State Street® SPDR® S&P MIDCAP 400® ETF Trust (MDY, by State Street (SPDR)) holds 399. They have 398 holdings in common, and by portfolio weight the two funds are 5.1% identical. In practical terms the pair is lightly overlapping, with most of each portfolio distinct.
- Overlap by Weight
- 5.1%Sum of the smaller weight of each shared holding
- Shared Holdings
- 398ITOT holds 2487 · MDY holds 399
- Weight in Shared Holdings
- ITOT 5%·MDY 105%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 ITOT
2089 of 2487 positions (94.7% of the fund) are not held by MDY. Showing the top 30 by weight.
Only in MDY
1 of 399 positions (0.2% of the fund) are not held by ITOT.
CRBGCorebridge Financial Inc.0.23%
Sector Breakdown
| Sector | ITOT | MDY |
|---|---|---|
| Information Technology | 30.8% | 15.6% |
| Industrials | 10.2% | 25.9% |
| Financials | 12.9% | 16.0% |
| Consumer Discretionary | 9.9% | 11.6% |
| Health Care | 9.9% | 10.3% |
| Other Sectors | 26.0% | 25.7% |
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 |
|---|---|---|---|---|---|---|---|
| ITOT | +3.3% | +14.6% | +24.1% | +20.9% | +12.3% | +14.9% | 0.97% |
| MDY | +3.1% | +18.1% | +25.6% | +14.2% | +8.8% | +10.9% | 0.99% |
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 ITOT vs MDY →
Shared Holdings(398)
The top 10 shared positions account for 7% of the overlap, led by FTI, CW and UTHR.
 FTITechnipFMC plc | 0.04% | 0.76% | 0.04% |
|---|---|---|---|
 CWCurtiss-Wright Corporation | 0.04% | 0.72% | 0.04% |
 UTHRUnited Therapeutics Corporation | 0.04% | 0.62% | 0.04% |
 XPOXPO, Inc. | 0.04% | 0.63% | 0.04% |
 WWDWoodward, Inc. | 0.03% | 0.60% | 0.03% |
 RGLDRoyal Gold, Inc. | 0.03% | 0.49% | 0.03% |
 USFDUS Foods Holding Corp. | 0.03% | 0.64% | 0.03% |
 BURLBurlington Stores, Inc. | 0.03% | 0.64% | 0.03% |
 MTZMasTec, Inc. | 0.03% | 0.44% | 0.03% |
 ATIATI, Inc. | 0.03% | 0.83% | 0.03% |
 CRSCarpenter Technology Corporation | 0.03% | 0.76% | 0.03% |
 TWLOTwilio, Inc., Class A | 0.03% | 0.80% | 0.03% |
 NVTnVent Electric plc | 0.03% | 0.72% | 0.03% |
 ILMNIllumina, Inc. | 0.03% | 0.80% | 0.03% |
 BWXTBWX Technologies, Inc. | 0.03% | 0.42% | 0.03% |
 FNFabrinet | 0.03% | 0.53% | 0.03% |
 PEverpure, Inc., Class A | 0.03% | 0.75% | 0.03% |
 RBARB Global, Inc. | 0.03% | 0.47% | 0.03% |
 NXTNextpower, Inc., Class A | 0.03% | 0.40% | 0.03% |
 CDECoeur Mining, Inc. | 0.03% | 0.44% | 0.03% |
 ENTGEntegris, Inc. | 0.03% | 0.59% | 0.03% |
 AAAlcoa Corporation | 0.03% | 0.68% | 0.03% |
 RBCRBC Bearings Incorporated | 0.03% | 0.49% | 0.03% |
 OVVOvintiv, Inc. | 0.03% | 0.45% | 0.03% |
 THCTenet Healthcare Corporation | 0.03% | 0.60% | 0.03% |
Showing the top 250 of 398 shared holdings by overlap weight.
Frequently Asked Questions
How much do ITOT and MDY overlap?
ITOT and MDY overlap by 5.1% of portfolio weight. They share 398 holdings (ITOT holds 2487 positions and MDY holds 399), based on each fund's latest SEC-reported holdings.
Is it redundant to own both ITOT and MDY?
The two portfolios are 5.1% 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 ITOT and MDY?
The largest positions held by both funds are FTI, CW, UTHR, XPO and WWD. Together the top 10 shared positions account for 7% of the total overlap.
What does ITOT own that MDY doesn't?
2089 positions (94.7% of ITOT) are unique to ITOT, led by NVDA, AAPL and MSFT. In the other direction, 1 positions (0.2% of MDY) are unique to MDY.