MDY vs SPY: Holdings Overlap
MDYState Street® SPDR® S&P MIDCAP 400® ETF Trust
State Street (SPDR) · 399 holdings · $27.1B · as of 2026-08-06
SPYState Street® SPDR® S&P 500® ETF Trust
State Street (SPDR) · 504 holdings · $812.0B · as of 2026-08-06
How similar are MDY and SPY?
State Street® SPDR® S&P MIDCAP 400® ETF Trust (MDY, by State Street (SPDR)) holds 399 positions; State Street® SPDR® S&P 500® ETF Trust (SPY, by State Street (SPDR)) holds 504. They have 0 holdings in common, and by portfolio weight the two funds are 0.0% identical. In practical terms the pair is essentially distinct, holding almost none of the same securities.
- Overlap by Weight
- 0.0%Sum of the smaller weight of each shared holding
- Shared Holdings
- 0MDY holds 399 · SPY holds 504
- Weight in Shared Holdings
- MDY 0%·SPY 0%Share of each fund's weight in stocks both funds own
Based on each fund's latest official holdings. How is this calculated?
What makes each fund different
Only in MDY
399 of 399 positions (105.1% of the fund) are not held by SPY. Showing the top 30 by weight.
Sector Breakdown
| Sector | MDY | SPY |
|---|---|---|
| Information Technology | 15.6% | 37.6% |
| Industrials | 25.9% | 8.8% |
| Financials | 16.0% | 12.3% |
| Consumer Discretionary | 11.6% | 9.3% |
| Health Care | 10.3% | 8.9% |
| Other Sectors | 25.7% | 23.1% |
Share of each fund's portfolio weight by GICS-style sector, compiled from issuer fund data and our own classification of the holdings, not the issuers' published sector charts.
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| MDY | +3.1% | +18.1% | +25.6% | +14.2% | +8.8% | +10.9% | 0.99% |
| SPY | +3.4% | +14.0% | +23.7% | +21.2% | +13.3% | +15.3% | 0.97% |
Total returns including dividends, from adjusted daily closes as of 2026-08-07. 3Y/5Y/10Y are annualized. Yield is trailing-12-month distributions over the last close. Past performance does not predict future results.
Project the growth of $10,000 in MDY vs SPY →
Shared Holdings(0)
These two funds have no holdings in common.
Frequently Asked Questions
How much do MDY and SPY overlap?
MDY and SPY overlap by 0.0% of portfolio weight. They share 0 holdings (MDY holds 399 positions and SPY holds 504), based on each fund's latest SEC-reported holdings.
Is it redundant to own both MDY and SPY?
The two portfolios are 0.0% identical by weight. Owning both is genuine diversification: the funds hold almost none of the same securities.
What does MDY own that SPY doesn't?
399 positions (105.1% of MDY) are unique to MDY, led by ATI, TWLO and ILMN. In the other direction, 504 positions (99.9% of SPY) are unique to SPY.