MDY vs SPMD overlap - what they share and where they differ
MDY and SPMD share 97.4% of their weight across 391 common positions, read from what each fund reported to the SEC.
Each week Ploutos reads the reported positions of the largest US equity ETFs and measures, pair by pair, the weight they share: for every stock both funds hold, the smaller of the two weights counts. Two funds tracking the same index land near 100%. A sector fund inside a broad index fund lands at roughly that sector's weight.
MDY and SPMD
97.4%
391 shared positions
MDY
State Street SPDR S&P MidCap 400SM ETF Trust
Reported positions cover 99% of the fund, 400 positions · Jun 30, 2026
Top 10: 7.7%·Holdings of MDY
SPMD
State Street(R) SPDR(R) Portfolio S&P 400(TM) Mid Cap ETF
Reported positions cover 100% of the fund, 400 positions · Jun 30, 2026
Top 10: 7.7%·Holdings of SPMD
Reported positions cover MDY 99%, SPMD 100% of each fund. An overlap cannot exceed the smaller coverage, so a low figure can mean little overlap or thin reporting.
SPMD vs MDY side by side
MDYState Street SPDR S&P MidCap 400SM ETF Trust
400
stock positions reported to the SEC
2.1% of its weight is in 9 names SPMD does not hold
SPMDState Street(R) SPDR(R) Portfolio S&P 400(TM) Mid Cap ETF
400
stock positions reported to the SEC
2.1% of its weight is in 9 names MDY does not hold
Where each fund's weight sits
Largest sectors for both funds
No sector differs by more than a point between the two.
The figures side by side
| MDY | SPMD | |
|---|---|---|
| Filing date | Jun 30, 2026 | Jun 30, 2026 |
| Stock positions reported | 400 | 400 |
| Weight of the ten largest | 7.7% | 7.7% |
| Largest position | TWLO 0.9% | TWLO 0.9% |
| Held alone | 9 positions, 2.1% | 9 positions, 2.1% |
| Covered by stock positions | 99% | 100% |
Holdings they share
| Stock | In MDY | In SPMD | Counted |
|---|---|---|---|
| TWLOTWILIO INC | 0.86% | 0.86% | 0.86% |
| CRSCARPENTER TECHNOLOGY CORP | 0.84% | 0.84% | 0.84% |
| MKSIMKS INC | 0.82% | 0.83% | 0.82% |
| CWCURTISS-WRIGHT CORP | 0.77% | 0.77% | 0.77% |
| ENTGENTEGRIS INC | 0.75% | 0.76% | 0.75% |
| NVENT ELECTRIC PLC | 0.75% | 0.76% | 0.75% |
| ATIATI INC | 0.74% | 0.74% | 0.74% |
| FTITECHNIPFMC PLC | 0.73% | 0.73% | 0.73% |
| ILMNILLUMINA INC | 0.73% | 0.73% | 0.73% |
| STRLSTERLING INFRASTRUCTURE INC | 0.71% | 0.71% | 0.71% |
What each holds alone
The heaviest positions one fund reports and the other does not.
Only in MDY
Only in SPMD
Questions people ask
Is MDY the same as SPMD?
97.4% of their weight sits in the same 391 holdings. MDY also reports WPC, DICKS SPORTING GOODS INC, CSL, which the other does not. SPMD also reports WP CAREY INC, DKS, CARLISLE COS INC, which the other does not.
How is the overlap between MDY and SPMD measured?
For every stock both funds report, the smaller of the two weights counts, and the sum is the overlap. The reported positions cover 99% of MDY and 100% of SPMD, so the number cannot exceed the smaller coverage.
Which holds more, SPMD or MDY?
MDY reports 400 stock positions and SPMD reports 400. 2.1% of MDY's weight sits in names SPMD does not hold, and 2.1% of SPMD's weight in names MDY does not hold. The ten largest positions are 7.7% of MDY and 7.7% of SPMD.
How do MDY and SPMD differ by sector?
No sector differs by more than a point between the two. Sectors come from each holding's SIC code in its SEC record, summed by the weight the fund reports.
Where do the numbers come from?
From each fund's own N-PORT filing to the SEC, which lists every position and its weight. The comparison uses every equity position the fund reports; cash, futures and bonds are not counted, which is why a coverage figure sits next to every result. Holdings change between filings.
Other pairs with these funds
MDY against other funds in the table
SPMD against other funds in the table
Add a third fund in the tool·All fund pairs
Descriptive data from public SEC filings. Nothing on this page is a recommendation to buy, sell or hold any fund or stock, and holdings change between filings.