CTSO vs SPY: Correlation
Measured on weekly returns over the past three years, Cytosorbents Corporation (CTSO) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.19, a weak link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are CTSO and SPY?
On 3 years of weekly data the CTSO/SPY correlation comes out at 0.19, weak. The link has tightened recently: the 1-year correlation (0.41) runs above the 3-year figure (0.19). The 5-year figure is 0.21, and annualized covariance runs at 205.1 %².
SPY is close to the least connected end of CTSO's tracked universe, ranking #7 of 10. Their recent paths diverged sharply: over the last 12 months SPY outperformed by 84.0 percentage points (-63.4% for CTSO against +20.6% for SPY). One caveat on sizing: CTSO is 5.2 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.
CTSO vs SPY: side by side
| CTSO (Cytosorbents Corporation) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | -63.4% | +20.6% |
| 5-year return | -96.4% | +82.4% |
| Volatility (ann.) | 75.9% | 14.5% |
| Beta vs S&P 500 | 0.98 | 1.00 |
| Max drawdown (3Y) | -87.9% | -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 | CTSO | SPY |
|---|---|---|
| 2022 | -63.0% | -18.2% |
| 2023 | -28.4% | +26.2% |
| 2024 | -18.0% | +24.9% |
| 2025 | -29.8% | +17.7% |
| 2026 | -46.7% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are CTSO and SPY good diversifiers for each other?
Yes. With a correlation of 0.19, CTSO and SPY have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
FAQ
What is the correlation between CTSO and SPY?
The CTSO/SPY correlation stands at 0.19 on a 3-year window (1 year: 0.41, 5 years: 0.21), computed from weekly returns as of 2026-08-27.
Is SPY a good diversifier for CTSO?
Yes. With a correlation of 0.19, CTSO and SPY have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
What does a correlation of 0.19 mean?
On the −1 to +1 scale, 0.19 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: CTSO correlations · SPY correlations
