HTOO vs SPY: Correlation
Fusion Fuel Green PLC (HTOO) and SPDR S&P 500 ETF Trust (SPY) show a weak relationship: their 3-year correlation of weekly returns is 0.10.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are HTOO and SPY?
On 3 years of weekly data the HTOO/SPY correlation comes out at 0.10, weak. The link has tightened recently: the 1-year correlation (0.40) runs above the 3-year figure (0.10). The 5-year figure is 0.14, and annualized covariance runs at 188.0 %².
SPY is close to the least connected end of HTOO's tracked universe, ranking #7 of 11. Correlation aside, the last 12 months split them widely, with SPY ahead by 70.8 points (-50.2% versus +20.6%). Note the risk asymmetry: HTOO runs 8.7 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.
HTOO vs SPY: side by side
| HTOO (Fusion Fuel Green PLC) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | -50.2% | +20.6% |
| 5-year return | -99.5% | +82.4% |
| Volatility (ann.) | 126.6% | 14.5% |
| Beta vs S&P 500 | 0.90 | 1.00 |
| Max drawdown (3Y) | -97.7% | -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 | HTOO | SPY |
|---|---|---|
| 2022 | -46.5% | -18.2% |
| 2023 | -74.7% | +26.2% |
| 2024 | -49.7% | +24.9% |
| 2025 | -83.1% | +17.7% |
| 2026 | -39.6% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are HTOO and SPY good diversifiers for each other?
Yes. With a correlation of 0.10, HTOO and SPY have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
FAQ
What is the correlation between HTOO and SPY?
As of 2026-08-27, the correlation of weekly returns between HTOO and SPY is 0.10 over 3 years, 0.40 over 1 year and 0.14 over 5 years.
Is SPY a good diversifier for HTOO?
Yes. With a correlation of 0.10, HTOO and SPY have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
What does a correlation of 0.10 mean?
On the −1 to +1 scale, 0.10 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.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/htoo-vs-spy.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/htoo-vs-spy/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: HTOO correlations · SPY correlations
