IJR vs MDY: how much do they overlap?
iShares Core S&P Small-Cap ETF (IJR) · SPDR S&P MIDCAP 400 ETF Trust (MDY)
overlap by weight · 4 shared holdings
IJR: 605 holdings (as of 2026-03-31) · MDY: 400 holdings (as of 09-Jul-2026)
Note: the two funds' latest official filings have different dates, which can understate overlap slightly for funds tracking similar indexes.
Low overlap
What this means
IJR and MDY hold mostly different stocks. Combining them genuinely spreads your exposure across different parts of the market.
Overlap by weight sums the smaller of the two funds' weights for every stock they both hold — it answers "how much of my money is in the same stocks either way?" See methodology.
Top shared holdings
| Company | Ticker | in IJR | in MDY |
|---|---|---|---|
| Semtech Corporation | SMTC | 0.46% | 0.36% |
| DigitalOcean Holdings Inc | DOCN | 0.44% | 0.32% |
| Sanmina Corp | SANM | 0.46% | 0.32% |
| Viavi Solutions Inc | VIAV | 0.5% | 0.28% |
FAQ
How much do IJR and MDY overlap?
IJR and MDY have a 1.3% overlap by weight, sharing 4 holdings (out of 605 in IJR and 400 in MDY), based on official issuer holdings as of 2026-03-31.
What does 1.3% overlap mean?
IJR and MDY hold mostly different stocks. Combining them genuinely spreads your exposure across different parts of the market.
Which stocks do IJR and MDY both hold?
The largest shared positions are Semtech Corporation, DigitalOcean Holdings Inc, Sanmina Corp, Viavi Solutions Inc. The full list of top shared holdings with weights in each fund is shown on this page.