IVOO vs MDY: Holdings Overlap
IVOOVanguard S&P Mid-cap 400 Index Fund
Vanguard · 400 holdings · $3.9B · as of 2026-05-31
MDYState Street® SPDR® S&P MIDCAP 400® ETF Trust
State Street (SPDR) · 399 holdings · $27.1B · as of 2026-08-06
Holdings snapshots are 67 days apart (IVOO: 2026-05-31, 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 IVOO and MDY?
Vanguard S&P Mid-cap 400 Index Fund (IVOO, by Vanguard) holds 400 positions; State Street® SPDR® S&P MIDCAP 400® ETF Trust (MDY, by State Street (SPDR)) holds 399. They have 387 holdings in common, and by portfolio weight the two funds are 91.1% identical. In practical terms the pair is essentially interchangeable, so holding both adds little diversification.
- Overlap by Weight
- 91.1%Sum of the smaller weight of each shared holding
- Shared Holdings
- 387IVOO holds 400 · MDY holds 399
- Weight in Shared Holdings
- IVOO 96%·MDY 101%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 IVOO
13 of 400 positions (3.4% of the fund) are not held by MDY.
Sector Breakdown
| Sector | IVOO | MDY |
|---|---|---|
| Industrials | 25.6% | 25.9% |
| Financials | 14.3% | 16.0% |
| Information Technology | 15.7% | 15.6% |
| Consumer Discretionary | 11.1% | 11.6% |
| Health Care | 8.7% | 10.3% |
| Other Sectors | 24.4% | 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 |
|---|---|---|---|---|---|---|---|
| IVOO | +3.1% | +18.5% | +26.0% | +14.6% | +9.0% | +11.2% | 1.14% |
| 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 IVOO vs MDY →
Shared Holdings(387)
The top 10 shared positions account for 8% of the overlap, led by TWLO, FTI and NVT.
 TWLOTwilio, Inc., Class A | 0.82% | 0.80% | 0.80% |
|---|---|---|---|
 FTITechnipFMC PLC USD1 | 0.79% | 0.76% | 0.76% |
 NVTNVent Electric PLC COM USD0.01 | 0.77% | 0.72% | 0.72% |
 CWCurtiss-Wright Corporation | 0.79% | 0.72% | 0.72% |
 PEverpure, Inc., Class A | 0.71% | 0.75% | 0.71% |
 ILMNIllumina Inc COM | 0.71% | 0.80% | 0.71% |
 ATIATI Inc COM | 0.68% | 0.83% | 0.68% |
 CRSCarpenter Technology Corporation COM | 0.67% | 0.76% | 0.67% |
 XPOXPO Inc COM | 0.72% | 0.63% | 0.63% |
 UTHRUnited Therapeutics Corporation COM | 0.68% | 0.62% | 0.62% |
 OKTAOkta Inc. Class A | 0.60% | 0.66% | 0.60% |
 ENTGEntegris Inc COM | 0.60% | 0.59% | 0.59% |
 WWDWoodward Inc. COM | 0.59% | 0.60% | 0.59% |
 BURLBurlington Stores Inc. COM | 0.57% | 0.64% | 0.57% |
 AAAlcoa Corporation COM | 0.57% | 0.68% | 0.57% |
 RSReliance Inc COM | 0.57% | 0.58% | 0.57% |
 MTSIMACOM Technology Solutions Holdings Inc. COM | 0.67% | 0.54% | 0.54% |
 MKSIMKS Inc. COM | 0.62% | 0.54% | 0.54% |
 FNFabrinet COM USD0.01 | 0.67% | 0.53% | 0.53% |
 SNXTD SYNNEX Corporation | 0.56% | 0.53% | 0.53% |
 USFDUS Foods Holding Corp COM | 0.51% | 0.64% | 0.51% |
 WCCWesco International, Inc. COM | 0.50% | 0.50% | 0.50% |
 RBCRBC Bearings Incorporated | 0.52% | 0.49% | 0.49% |
 RGLDRoyal Gold, Inc. COM | 0.52% | 0.49% | 0.49% |
 LSCCLattice Semiconductor Corporation COM | 0.57% | 0.48% | 0.48% |
Showing the top 250 of 387 shared holdings by overlap weight.
Frequently Asked Questions
How much do IVOO and MDY overlap?
IVOO and MDY overlap by 91.1% of portfolio weight. They share 387 holdings (IVOO holds 400 positions and MDY holds 399), based on each fund's latest SEC-reported holdings.
Is it redundant to own both IVOO and MDY?
The two portfolios are 91.1% identical by weight. Owning both is largely redundant: they are close to the same portfolio, so a second position mostly duplicates the first.
What are the biggest shared holdings of IVOO and MDY?
The largest positions held by both funds are TWLO, FTI, NVT, CW and P. Together the top 10 shared positions account for 8% of the total overlap.
What does IVOO own that MDY doesn't?
13 positions (3.4% of IVOO) are unique to IVOO, led by FLEX, LAMR and 28T. In the other direction, 12 positions (4.0% of MDY) are unique to MDY.