EFOI vs SPY: Correlation
How closely do Energy Focus, Inc. (EFOI) and SPDR S&P 500 ETF Trust (SPY) trade together? Their weekly returns over three years give a correlation of 0.18, which is weak.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are EFOI and SPY?
On 3 years of weekly data the EFOI/SPY correlation comes out at 0.18, weak. The link has tightened recently: the 1-year correlation (0.34) runs above the 3-year figure (0.18). The 5-year figure is 0.15, and annualized covariance runs at 410.4 %².
Within EFOI's tracked universe of 17 assets, SPY comes in at #10 by 3-year correlation. The trailing year gives SPY the advantage: +13.2% versus +20.6%, a 7.4-point spread. Note the risk asymmetry: EFOI runs 10.9 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.
EFOI vs SPY: side by side
| EFOI (Energy Focus, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +13.2% | +20.6% |
| 5-year return | -87.5% | +82.4% |
| Volatility (ann.) | 158.7% | 14.5% |
| Beta vs S&P 500 | 1.96 | 1.00 |
| Max drawdown (3Y) | -58.2% | -18.8% |
| Market cap | – | – |
| P/E (trailing) | – | – |
| 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 | EFOI | SPY |
|---|---|---|
| 2022 | -92.5% | -18.2% |
| 2023 | -32.6% | +26.2% |
| 2024 | -21.2% | +24.9% |
| 2025 | +94.1% | +17.7% |
| 2026 | +25.5% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are EFOI and SPY good diversifiers for each other?
By historical standards, yes. A correlation of 0.18 means the two rarely move for the same reasons.
FAQ
What is the correlation between EFOI and SPY?
As of 2026-08-27, the correlation of weekly returns between EFOI and SPY is 0.18 over 3 years, 0.34 over 1 year and 0.15 over 5 years.
Is SPY a good diversifier for EFOI?
By historical standards, yes. A correlation of 0.18 means the two rarely move for the same reasons.
What does a correlation of 0.18 mean?
Correlation ranges from −1 to +1. Values near +1 mean two assets move together, near 0 that they move independently, and negative values that they tend to move in opposite directions. It measures co-movement, not performance.
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Related comparisons
Hubs: EFOI correlations · SPY correlations
