MDY vs VXF: 41% overlap
SPDR S&P MidCap 400 ETF Trust and Vanguard Extended Market ETF share 41.1% 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 1.6. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
MDY and VXF hold 399 of the same securities. The ten contributing most to the overlap figure:
| Holding | in MDY | in VXF | Δ |
|---|---|---|---|
| TWLO | 0.8% | 0.4% | 0.4% |
| CRS | 0.8% | 0.3% | 0.5% |
| MKSI | 0.6% | 0.3% | 0.3% |
| CW | 0.8% | 0.3% | 0.5% |
| ENTG | 0.6% | 0.3% | 0.3% |
| NVT | 0.7% | 0.3% | 0.4% |
| ATI | 0.8% | 0.3% | 0.5% |
| ILMN | 0.8% | 0.3% | 0.5% |
| FTI | 0.8% | 0.3% | 0.5% |
| STRL | 0.6% | 0.3% | 0.3% |
Where MDY and VXF 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 | VXF | Δ |
|---|---|---|---|
| Industrials | 25.4% | 19.8% | +5.5pp |
| Information Technology | 13.8% | 17.6% | −3.8pp |
| Cash and/or Derivatives | 0.0% | 3.8% | −3.8pp |
| Health Care | 9.7% | 13.2% | −3.5pp |
| Communication Services | 1.5% | 4.5% | −2.9pp |
| Real Estate | 6.9% | 4.8% | +2.1pp |
| Consumer Discretionary | 10.2% | 8.8% | +1.5pp |
| Materials | 5.4% | 4.1% | +1.4pp |
Δ is MDY minus VXF, 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
0.0% of MDY by weight, held in no part of VXF.
58.9% of VXF 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 | VXF | |
|---|---|---|
| Top 10 holdings | 7.6% | 10.6% |
| Positions held | 400 | 3,327 |
| Cost per $10,000 held, per year | $23 | $5 |
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 VXF overlap?
MDY and VXF overlap 41.1% by portfolio weight — moderate overlap. They share 399 holdings. The figure comes from current issuer holdings files (MDY as of 2026-07-23, VXF as of 2026-06-30).
How is the overlap between MDY and VXF 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 VXF 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 VXF?
That depends on your goals — we state facts, not advice. At 41.1% overlap, each fund still contributes meaningfully distinct exposure.
What does MDY own that VXF doesn't?
MDY holds 400 positions and VXF holds 3,327; 0 of MDY's positions don't appear in VXF at all, and they are 0.0% of MDY by weight.
You probably hold more than two funds
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Related comparisons
Sources: issuer holdings files, MDY as of 2026-07-23, VXF as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.