IONS vs SPY: Correlation
Measured on weekly returns over the past three years, Ionis Pharmaceuticals, Inc. (IONS) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.23, a weak link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are IONS and SPY?
Across a 3-year window, the weekly returns of IONS and SPY correlate at 0.23, weak. The link has loosened recently: the 1-year correlation (0.08) runs below the 3-year figure (0.23). Stretching to 5 years gives 0.27, with an annualized covariance of 151.0 %².
By 3-year correlation, SPY places #8 of the 13 assets tracked against IONS. The last year tells two different stories: IONS led by 25.4 percentage points, +46.0% for IONS against +20.6% for SPY. One caveat on sizing: IONS is 3.1 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.
IONS vs SPY: side by side
| IONS (Ionis Pharmaceuticals, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +46.0% | +20.6% |
| 5-year return | +59.5% | +82.4% |
| Volatility (ann.) | 44.7% | 14.5% |
| Beta vs S&P 500 | 0.72 | 1.00 |
| Max drawdown (3Y) | -52.4% | -18.8% |
| Market cap | $10.4B | – |
| 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 | IONS | SPY |
|---|---|---|
| 2022 | +24.1% | -18.2% |
| 2023 | +33.9% | +26.2% |
| 2024 | -30.9% | +24.9% |
| 2025 | +126.3% | +17.7% |
| 2026 | -21.1% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are IONS and SPY good diversifiers for each other?
A fair diversifier. At 0.23, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
FAQ
What is the correlation between IONS and SPY?
The IONS/SPY correlation stands at 0.23 on a 3-year window (1 year: 0.08, 5 years: 0.27), computed from weekly returns as of 2026-08-27.
Is SPY a good diversifier for IONS?
A fair diversifier. At 0.23, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
What does a correlation of 0.23 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.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/ions-vs-spy.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/ions-vs-spy/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: IONS correlations · SPY correlations
