BLDP vs SPY: Correlation
Measured on weekly returns over the past three years, Ballard Power Systems, Inc. (BLDP) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.35, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are BLDP and SPY?
Across a 3-year window, the weekly returns of BLDP and SPY correlate at 0.35, moderate. The relationship has been stable: the 1-year correlation (0.40) sits close to the 3-year figure. Stretching to 5 years gives 0.45, with an annualized covariance of 337.4 %².
Among the 23 assets we track against BLDP, SPY ranks #14 by 3-year correlation. Their 12-month results are close: +15.8% for BLDP against +20.6% for SPY. One caveat on sizing: BLDP is 4.6 times as volatile as the other leg, so an equal-dollar split is far from equal-risk.
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.
BLDP vs SPY: side by side
| BLDP (Ballard Power Systems, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +15.8% | +20.6% |
| 5-year return | -85.8% | +82.4% |
| Volatility (ann.) | 66.3% | 14.5% |
| Beta vs S&P 500 | 1.62 | 1.00 |
| Max drawdown (3Y) | -76.4% | -18.8% |
| Market cap | $0.7B | – |
| 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 | BLDP | SPY |
|---|---|---|
| 2022 | -61.9% | -18.2% |
| 2023 | -22.8% | +26.2% |
| 2024 | -55.1% | +24.9% |
| 2025 | +53.0% | +17.7% |
| 2026 | -7.9% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are BLDP and SPY good diversifiers for each other?
Reasonably. At 0.35, BLDP and SPY keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
FAQ
What is the correlation between BLDP and SPY?
As of 2026-08-27, the correlation of weekly returns between BLDP and SPY is 0.35 over 3 years, 0.40 over 1 year and 0.45 over 5 years.
Is SPY a good diversifier for BLDP?
Reasonably. At 0.35, BLDP and SPY keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
What does a correlation of 0.35 mean?
A reading of 0.35 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
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Related comparisons
Hubs: BLDP correlations · SPY correlations
