ALT vs SPY: Correlation
How closely do Altimmune, Inc. (ALT) and SPDR S&P 500 ETF Trust (SPY) trade together? Their weekly returns over three years give a correlation of 0.29, which is weak.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are ALT and SPY?
On 3 years of weekly data the ALT/SPY correlation comes out at 0.29, weak. The relationship has been stable: the 1-year correlation (0.31) sits close to the 3-year figure. The 5-year figure is 0.19, and annualized covariance runs at 398.3 %².
Out of 13 assets tracked against ALT, SPY lands near the bottom at #9. Correlation aside, the last 12 months split them widely, with SPY ahead by 32.3 points (-11.7% versus +20.6%). One caveat on sizing: ALT is 6.5 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.
ALT vs SPY: side by side
| ALT (Altimmune, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | -11.7% | +20.6% |
| 5-year return | -77.0% | +82.4% |
| Volatility (ann.) | 94.4% | 14.5% |
| Beta vs S&P 500 | 1.91 | 1.00 |
| Max drawdown (3Y) | -81.2% | -18.8% |
| Market cap | $0.6B | – |
| 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 | ALT | SPY |
|---|---|---|
| 2022 | +79.6% | -18.2% |
| 2023 | -31.6% | +26.2% |
| 2024 | -35.9% | +24.9% |
| 2025 | -49.9% | +17.7% |
| 2026 | -10.2% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are ALT and SPY good diversifiers for each other?
Yes, to a useful degree: a correlation of 0.29 leaves real independence between the two, which historically damped combined volatility.
FAQ
What is the correlation between ALT and SPY?
The ALT/SPY correlation stands at 0.29 on a 3-year window (1 year: 0.31, 5 years: 0.19), computed from weekly returns as of 2026-08-27.
Is SPY a good diversifier for ALT?
Yes, to a useful degree: a correlation of 0.29 leaves real independence between the two, which historically damped combined volatility.
What does a correlation of 0.29 mean?
On the −1 to +1 scale, 0.29 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: ALT correlations · SPY correlations
