MDY vs XLB: 0% overlap
SPDR S&P MidCap 400 ETF Trust and Materials Select Sector SPDR Fund share 0.0% 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 XLB hold 0 of the same securities. The ten contributing most to the overlap figure:
| Holding | in MDY | in XLB | Δ |
|---|
Where MDY and XLB 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 | XLB | Δ |
|---|---|---|---|
| Materials | 5.4% | 99.8% | −94.4pp |
| Industrials | 25.4% | 0.0% | +25.4pp |
| Financials | 14.8% | 0.0% | +14.8pp |
| Information Technology | 13.8% | 0.0% | +13.8pp |
| Consumer Discretionary | 10.2% | 0.0% | +10.2pp |
| Health Care | 9.7% | 0.0% | +9.7pp |
| Real Estate | 6.9% | 0.0% | +6.9pp |
| Energy | 4.9% | 0.0% | +4.9pp |
Δ is MDY minus XLB, 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
98.9% of MDY by weight, held in no part of XLB.
100.0% of XLB 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 | XLB | |
|---|---|---|
| Top 10 holdings | 7.6% | 57.4% |
| Positions held | 400 | 28 |
| Cost per $10,000 held, per year | $23 | $8 |
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 XLB overlap?
MDY and XLB overlap 0.0% by portfolio weight — largely distinct portfolios. They share 0 holdings. The figure comes from current issuer holdings files (MDY as of 2026-07-23, XLB as of 2026-07-23).
How is the overlap between MDY and XLB 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 XLB 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 XLB?
That depends on your goals — we state facts, not advice. At 0.0% overlap, each fund still contributes meaningfully distinct exposure.
What does MDY own that XLB doesn't?
MDY holds 400 positions and XLB holds 28; 399 of MDY's positions don't appear in XLB at all, and they are 98.9% of MDY by weight.
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Related comparisons
Sources: issuer holdings files, MDY as of 2026-07-23, XLB as of 2026-07-23. Weights are fractions of each fund. Diagnostics, not advice.