MDY vs VTWAX: 4% overlap
SPDR S&P MidCap 400 ETF Trust and Vanguard Total World Stock Index Admiral share 3.7% 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 VTWAX hold 397 of the same securities. The ten contributing most to the overlap figure:
| Holding | in MDY | in VTWAX | Δ |
|---|---|---|---|
| ALV | 0.2% | 0.2% | 0.1% |
| CFR | 0.3% | 0.1% | 0.2% |
| AAL | 0.2% | 0.0% | 0.2% |
| CSL | 0.4% | 0.0% | 0.3% |
| G | 0.1% | 0.0% | 0.1% |
| NXT | 0.4% | 0.0% | 0.4% |
| ORA | 0.2% | 0.0% | 0.1% |
| MKSI | 0.6% | 0.0% | 0.6% |
| TWLO | 0.8% | 0.0% | 0.8% |
| CRS | 0.8% | 0.0% | 0.8% |
Where MDY and VTWAX 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 | VTWAX | Δ |
|---|---|---|---|
| Information Technology | 13.8% | 30.1% | −16.3pp |
| Industrials | 25.4% | 11.5% | +13.9pp |
| Communication Services | 1.5% | 7.0% | −5.4pp |
| Real Estate | 6.9% | 2.1% | +4.8pp |
| Unclassified | 0.0% | 3.8% | −3.8pp |
| Materials | 5.4% | 3.3% | +2.1pp |
| Health Care | 9.7% | 7.7% | +2.0pp |
| Energy | 4.9% | 3.0% | +1.9pp |
Δ is MDY minus VTWAX, 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
0.2% of MDY by weight, held in no part of VTWAX.
96.3% of VTWAX 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 | VTWAX | |
|---|---|---|
| Top 10 holdings | 7.6% | 20.5% |
| Positions held | 400 | 9,600 |
| Cost per $10,000 held, per year | $23 | $9 |
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 VTWAX overlap?
MDY and VTWAX overlap 3.7% by portfolio weight — largely distinct portfolios. They share 397 holdings. The figure comes from current issuer holdings files (MDY as of 2026-07-23, VTWAX as of 2026-06-30).
How is the overlap between MDY and VTWAX 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 VTWAX 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 VTWAX?
That depends on your goals — we state facts, not advice. At 3.7% overlap, each fund still contributes meaningfully distinct exposure.
What does MDY own that VTWAX doesn't?
MDY holds 400 positions and VTWAX holds 9,600; 2 of MDY's positions don't appear in VTWAX at all, and they are 0.2% of MDY by weight.
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Related comparisons
Sources: issuer holdings files, MDY as of 2026-07-23, VTWAX as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.