HOWL vs SPY: Correlation
Werewolf Therapeutics, Inc. (HOWL) and SPDR S&P 500 ETF Trust (SPY) show a weak relationship: their 3-year correlation of weekly returns is 0.16.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are HOWL and SPY?
Across a 3-year window, the weekly returns of HOWL and SPY correlate at 0.16, weak. The link has loosened recently: the 1-year correlation (0.02) runs below the 3-year figure (0.16). Stretching to 5 years gives 0.16, with an annualized covariance of 289.3 %².
Among the 10 assets we track against HOWL, SPY sits near the bottom by co-movement, at rank #6. Correlation aside, the last 12 months split them widely, with SPY ahead by 47.6 points (-27.0% versus +20.6%). Risk is not evenly split, since HOWL carries 8.6 times the volatility of the other side.
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.
HOWL vs SPY: side by side
| HOWL (Werewolf Therapeutics, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | -27.0% | +20.6% |
| 5-year return | -94.4% | +82.4% |
| Volatility (ann.) | 124.1% | 14.5% |
| Beta vs S&P 500 | 1.39 | 1.00 |
| Max drawdown (3Y) | -96.1% | -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 | HOWL | SPY |
|---|---|---|
| 2022 | -82.8% | -18.2% |
| 2023 | +88.3% | +26.2% |
| 2024 | -61.7% | +24.9% |
| 2025 | -57.2% | +17.7% |
| 2026 | +53.1% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are HOWL and SPY good diversifiers for each other?
Yes: at 0.16, the two have gone their own ways historically, which is what genuine diversification looks like.
FAQ
What is the correlation between HOWL and SPY?
The HOWL/SPY correlation stands at 0.16 on a 3-year window (1 year: 0.02, 5 years: 0.16), computed from weekly returns as of 2026-08-27.
Is SPY a good diversifier for HOWL?
Yes: at 0.16, the two have gone their own ways historically, which is what genuine diversification looks like.
What does a correlation of 0.16 mean?
On the −1 to +1 scale, 0.16 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: HOWL correlations · SPY correlations
