MDY vs VTI: 5% overlap
SPDR S&P MidCap 400 ETF Trust and Vanguard Total Stock Market ETF share 5.0% of their portfolios by weight — computed as Σ min(wA, wB) over every holding both funds own.
You would hold two tickers and get the diversification of 2.0. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
MDY and VTI hold 396 of the same securities. The ten contributing most to the overlap figure:
| Holding | in MDY | in VTI | Δ |
|---|---|---|---|
| TWLO | 0.8% | 0.0% | 0.7% |
| MKSI | 0.6% | 0.0% | 0.6% |
| CRS | 0.8% | 0.0% | 0.8% |
| CW | 0.8% | 0.0% | 0.7% |
| ENTG | 0.6% | 0.0% | 0.5% |
| NVT | 0.7% | 0.0% | 0.7% |
| ATI | 0.8% | 0.0% | 0.7% |
| FTI | 0.8% | 0.0% | 0.8% |
| MTZ | 0.6% | 0.0% | 0.6% |
| MTSI | 0.5% | 0.0% | 0.5% |
Where MDY and VTI differ
Sector weights as a share of each fund, ordered by the size of the gap rather than the size of the sector — two funds that overlap heavily still usually diverge somewhere.
| Sector | MDY | VTI | Δ |
|---|---|---|---|
| Information Technology | 13.8% | 35.2% | −21.4pp |
| Industrials | 25.4% | 10.4% | +15.0pp |
| Communication Services | 1.5% | 9.1% | −7.5pp |
| Real Estate | 6.9% | 2.2% | +4.6pp |
| Materials | 5.4% | 2.0% | +3.4pp |
| Financials | 14.8% | 11.9% | +3.0pp |
| Energy | 4.9% | 3.1% | +1.8pp |
| Consumer Staples | 3.1% | 4.3% | −1.2pp |
Δ is MDY minus VTI, in percentage points. Sector data is not published by every issuer, so “Unclassified” is a real category rather than a gap in the table.
What each fund holds alone
0.6% of MDY by weight, held in no part of VTI.
95.0% of VTI by weight, held in no part of MDY.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| MDY | VTI | |
|---|---|---|
| Top 10 holdings | 7.6% | 31.9% |
| Positions held | 400 | 3,495 |
| Cost per $10,000 held, per year | $23 | $3 |
Cost is the expense ratio applied to $10,000; it excludes any brokerage commission, bid-ask spread or tax consequence. Figures are facts about the funds, not a suggestion about which to hold.
Frequently asked
How much do MDY and VTI overlap?
MDY and VTI overlap 5.0% by portfolio weight — largely distinct portfolios. They share 396 holdings. The figure comes from current issuer holdings files (MDY as of 2026-07-23, VTI as of 2026-06-30).
How is the overlap between MDY and VTI calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If MDY holds a stock at 6% and VTI holds the same stock at 4%, 4% counts as shared. The result is bounded between 0% and 100%, and it is computed after looking through any fund-of-funds to the underlying holdings.
Is it redundant to hold both MDY and VTI?
That depends on your goals — we state facts, not advice. At 5.0% overlap, each fund still contributes meaningfully distinct exposure.
What does MDY own that VTI doesn't?
MDY holds 400 positions and VTI holds 3,495; 3 of MDY's positions don't appear in VTI at all, and they are 0.6% of MDY by weight.
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Related comparisons
Sources: issuer holdings files, MDY as of 2026-07-23, VTI as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.