SPY vs XFOR: Correlation
Measured on weekly returns over the past three years, SPDR S&P 500 ETF Trust (SPY) and X4 Pharmaceuticals, Inc. (XFOR) carry a correlation of 0.20, a weak link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are SPY and XFOR?
Over the past 3 years, SPY and XFOR moved with a correlation of 0.20, which is weak. The past 12 months show a tighter link (0.35) than the 3-year average (0.20). Over 5 years the correlation is 0.20, and the annualized covariance of weekly returns is 347.6 %².
By 3-year correlation, XFOR places #3302 of the 4755 assets tracked against SPY. The last year tells two different stories: SPY led by 20.6 percentage points, +20.6% for SPY against +0.0% for XFOR. One caveat on sizing: XFOR is 8.4 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.
SPY vs XFOR: side by side
| SPY (SPDR S&P 500 ETF Trust) | XFOR (X4 Pharmaceuticals, Inc.) | |
|---|---|---|
| 1-year return | +20.6% | +0.0% |
| 5-year return | +82.4% | -97.2% |
| Volatility (ann.) | 14.5% | 121.6% |
| Beta vs S&P 500 | 1.00 | 1.66 |
| Max drawdown (3Y) | -18.8% | -96.8% |
| Market cap | – | $0.4B |
| P/E (trailing) | – | 2.9 |
| Dividend yield | 1.01% | 0.00% |
| Expense ratio | 0.09% | – |
| Assets under management | $795.3B | – |
| Sector / category | ETF · US Large Cap | US Listed |
On the fund side, SPY sits in the Large Blend category at State Street Investment Management, with $795.3B under management, 504 holdings, a 0.09% expense ratio, a 1.01% trailing dividend yield.
Year-by-year returns
| Year | SPY | XFOR |
|---|---|---|
| 2022 | -18.2% | -56.6% |
| 2023 | +26.2% | -15.5% |
| 2024 | +24.9% | -12.5% |
| 2025 | +17.7% | -81.8% |
| 2026 | +13.7% | +5.8% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are SPY and XFOR good diversifiers for each other?
Yes, to a useful degree: a correlation of 0.20 leaves real independence between the two, which historically damped combined volatility.
FAQ
What is the correlation between SPY and XFOR?
Using weekly returns as of 2026-08-27: 0.20 over 3 years, with 0.35 over the last year and 0.20 over 5 years.
Is XFOR a good diversifier for SPY?
Yes, to a useful degree: a correlation of 0.20 leaves real independence between the two, which historically damped combined volatility.
What does a correlation of 0.20 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/spy-vs-xfor.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/spy-vs-xfor/)
Free with attribution; caching and terms are described in the API documentation.
Related comparisons
Hubs: SPY correlations · XFOR correlations
