GRN vs SPY: Correlation
Measured on weekly returns over the past three years, iPath Series B Carbon Exchange-Traded Notes (GRN) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.19, a weak link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are GRN and SPY?
On 3 years of weekly data the GRN/SPY correlation comes out at 0.19, weak. The past 12 months show a tighter link (0.30) than the 3-year average (0.19). The 5-year figure is 0.17, and annualized covariance runs at 82.9 %².
SPY is close to the least connected end of GRN's tracked universe, ranking #7 of 10. Over the last 12 months SPY came out ahead by 5.9 percentage points (+14.7% against +20.6%). Note the risk asymmetry: GRN runs 2.0 times the annualized volatility of the other leg, so equal-weighting the two is not an equal-risk position.
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.
GRN vs SPY: side by side
| GRN (iPath Series B Carbon Exchange-Traded Notes) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +14.7% | +20.6% |
| 5-year return | +36.8% | +82.4% |
| Volatility (ann.) | 29.5% | 14.5% |
| Beta vs S&P 500 | 0.40 | 1.00 |
| Max drawdown (3Y) | -40.7% | -18.8% |
| Market cap | – | – |
| P/E (trailing) | 3.5 | – |
| Dividend yield | 0.00% | 1.01% |
| Expense ratio | – | 0.09% |
| Assets under management | – | $795.3B |
| Sector / category | US Listed | ETF · US Large Cap |
SPY is a Large Blend fund from State Street Investment Management: $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | GRN | SPY |
|---|---|---|
| 2022 | -0.1% | -18.2% |
| 2023 | -3.0% | +26.2% |
| 2024 | -7.3% | +24.9% |
| 2025 | +20.3% | +17.7% |
| 2026 | -3.8% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are GRN and SPY good diversifiers for each other?
By historical standards, yes. A correlation of 0.19 means the two rarely move for the same reasons.
FAQ
What is the correlation between GRN and SPY?
Using weekly returns as of 2026-08-27: 0.19 over 3 years, with 0.30 over the last year and 0.17 over 5 years.
Is SPY a good diversifier for GRN?
By historical standards, yes. A correlation of 0.19 means the two rarely move for the same reasons.
What does a correlation of 0.19 mean?
On the −1 to +1 scale, 0.19 describes how much the two returns move together: +1 is lockstep, 0 is independence, negative values mean opposite directions. It says nothing about which performed better.
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Related comparisons
Hubs: GRN correlations · SPY correlations
