MDY vs TSPI: 1% overlap
SPDR S&P MidCap 400 ETF Trust and TSP I Fund — shown via international proxy share 1.3% 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 TSPI hold 46 of the same securities. The ten contributing most to the overlap figure:
| Holding | in MDY | in TSPI | Δ |
|---|---|---|---|
| CFR | 0.3% | 0.3% | 0.0% |
| ALV | 0.2% | 0.4% | 0.2% |
| AAL | 0.2% | 0.1% | 0.1% |
| G | 0.1% | 0.1% | 0.0% |
| ORA | 0.2% | 0.1% | 0.1% |
| CSL | 0.4% | 0.1% | 0.3% |
| NXT | 0.4% | 0.1% | 0.4% |
| MTN | 0.1% | 0.1% | 0.1% |
| RBA | 0.6% | 0.0% | 0.5% |
| VAL | 0.1% | 0.0% | 0.1% |
Where MDY and TSPI 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 | TSPI | Δ |
|---|---|---|---|
| Industrials | 25.4% | 13.8% | +11.5pp |
| Unclassified | 0.0% | 9.1% | −9.1pp |
| Information Technology | 13.8% | 20.9% | −7.1pp |
| Real Estate | 6.9% | 1.9% | +5.0pp |
| Financials | 14.8% | 19.7% | −4.9pp |
| Health Care | 9.7% | 5.3% | +4.4pp |
| Consumer Discretionary | 10.2% | 7.5% | +2.8pp |
| Cash and/or Derivatives | 0.0% | 2.5% | −2.5pp |
Δ is MDY minus TSPI, 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
89.9% of MDY by weight, held in no part of TSPI.
98.5% of TSPI 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 | TSPI | |
|---|---|---|
| Top 10 holdings | 7.6% | 16.3% |
| Positions held | 400 | 8,453 |
| 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 TSPI overlap?
MDY and TSPI overlap 1.3% by portfolio weight — largely distinct portfolios. They share 46 holdings. The figure comes from current issuer holdings files (MDY as of 2026-07-23, TSPI as of 2026-06-30).
How is the overlap between MDY and TSPI 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 TSPI 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 TSPI?
That depends on your goals — we state facts, not advice. At 1.3% overlap, each fund still contributes meaningfully distinct exposure.
What does MDY own that TSPI doesn't?
MDY holds 400 positions and TSPI holds 8,453; 353 of MDY's positions don't appear in TSPI at all, and they are 89.9% of MDY by weight.
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Related comparisons
Sources: issuer holdings files, MDY as of 2026-07-23, TSPI as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.