ICLN vs MDY: Correlation & Overlap
How closely do iShares Global Clean Energy ETF (ICLN) and SPDR S&P MidCap 400 ETF (MDY) trade together? Their weekly returns over three years give a correlation of 0.49, which is moderate. Looking through to holdings, 0.4% of the two portfolios is the same by weight.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are ICLN and MDY?
Over the past 3 years, ICLN and MDY moved with a correlation of 0.49, which is moderate. Little has changed lately, as the 1-year reading of 0.39 lands near the 3-year figure. Over 5 years the correlation is 0.57, and the annualized covariance of weekly returns is 193.7 %².
By 3-year correlation, MDY places #28 of the 78 assets tracked against ICLN. Over the last 12 months ICLN came out ahead by 7.3 percentage points (+25.6% against +18.3%). The relationship is regime-dependent: the rolling one-year correlation swung between 0.27 and 0.78 over the past three years, so this pair behaves very differently depending on the market environment.
How is this computed?
Pearson correlation on weekly returns: ρ(A,B) = cov(rA, rB) / (σA · σB), over windows of 52, 156 and 260 weeks. Covariance is annualized (×52) and expressed in %². Full definitions on the methodology page.
ICLN vs MDY: side by side
| ICLN (iShares Global Clean Energy ETF) | MDY (SPDR S&P MidCap 400 ETF) | |
|---|---|---|
| 1-year return | +25.6% | +18.3% |
| 5-year return | -18.4% | +47.5% |
| Volatility (ann.) | 24.0% | 16.5% |
| Beta vs S&P 500 | 0.78 | 0.91 |
| Max drawdown (3Y) | -34.6% | -24.0% |
| Dividend yield | 1.05% | 1.02% |
| Expense ratio | 0.39% | 0.23% |
| Assets under management | $2.3B | $26.5B |
| Sector / category | ETF · Thematic | ETF · US Small & Mid Cap |
ICLN is a Miscellaneous Sector fund from iShares: $2.3B under management, 102 holdings, a 0.39% expense ratio, a 1.05% trailing dividend yield. MDY, State Street Investment Management's Mid-Cap Blend fund, carries $26.5B under management, 400 holdings, a 0.23% expense ratio, a 1.02% trailing dividend yield.
Portfolio overlap between ICLN and MDY
The two portfolios are largely distinct: 0.4% of the funds' weight sits in the same underlying holdings (1 common positions). Correlation tells you they move together; overlap tells you why.
| Common holding | Weight in ICLN | Weight in MDY |
|---|---|---|
| NXT | 6.81% | 0.36% |
Largest positions held only by ICLN: FSLR (7.87%), 600900 (7.64%), BE (7.36%), ENPH (4.70%), VWS (4.36%). Only by MDY: TWLO (0.95%), P (0.94%), ILMN (0.93%), FTI (0.83%), ATI (0.80%).
Overlap = sum of the smaller of the two weights across common holdings, from issuer disclosures as of 2026-08-26. Top 1 common positions shown.
Year-by-year returns
| Year | ICLN | MDY |
|---|---|---|
| 2022 | -5.4% | -13.3% |
| 2023 | -20.4% | +16.1% |
| 2024 | -25.7% | +13.6% |
| 2025 | +47.0% | +7.2% |
| 2026 | +8.8% | +16.4% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are ICLN and MDY good diversifiers for each other?
A fair diversifier. At 0.49, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
FAQ
What is the correlation between ICLN and MDY?
The ICLN/MDY correlation stands at 0.49 on a 3-year window (1 year: 0.39, 5 years: 0.57), computed from weekly returns as of 2026-08-27.
Is MDY a good diversifier for ICLN?
A fair diversifier. At 0.49, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
How much do ICLN and MDY overlap?
Per the issuers' own portfolio disclosures (2026-08-26), the overlap is 0.4% by weight over 1 common positions.
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Related comparisons
Hubs: ICLN correlations · MDY correlations
