CERS vs IWM: Correlation
Measured on weekly returns over the past three years, Cerus Corporation (CERS) and iShares Russell 2000 ETF (IWM) carry a correlation of 0.59, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are CERS and IWM?
Across a 3-year window, the weekly returns of CERS and IWM correlate at 0.59, moderate. The past 12 months show a weaker link (0.42) than the 3-year average (0.59). Stretching to 5 years gives 0.56, with an annualized covariance of 829.5 %².
Few assets follow CERS as closely as IWM, which ranks #1 of 10 tracked partners. The last year tells two different stories: CERS led by 79.2 percentage points, +107.6% for CERS against +28.4% for IWM. Risk is not evenly split, since CERS carries 3.6 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.
CERS vs IWM: side by side
| CERS (Cerus Corporation) | IWM (iShares Russell 2000 ETF) | |
|---|---|---|
| 1-year return | +107.6% | +28.4% |
| 5-year return | -57.3% | +41.5% |
| Volatility (ann.) | 71.0% | 19.8% |
| Beta vs S&P 500 | 2.01 | 1.06 |
| Max drawdown (3Y) | -52.1% | -27.5% |
| Market cap | $0.5B | – |
| P/E (trailing) | – | – |
| Dividend yield | 0.00% | 0.91% |
| Expense ratio | – | 0.19% |
| Assets under management | – | $80.1B |
| Sector / category | US Listed | ETF · US Small & Mid Cap |
IWM, iShares's Small Blend fund, carries $80.1B under management, 1757 holdings, a 0.19% expense ratio, a 0.91% trailing dividend yield.
Year-by-year returns
| Year | CERS | IWM |
|---|---|---|
| 2022 | -46.4% | -20.5% |
| 2023 | -40.8% | +16.8% |
| 2024 | -28.7% | +11.4% |
| 2025 | +33.8% | +12.7% |
| 2026 | +32.0% | +22.3% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are CERS and IWM good diversifiers for each other?
Only partially. A correlation of 0.59 means CERS and IWM share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
FAQ
What is the correlation between CERS and IWM?
Using weekly returns as of 2026-08-27: 0.59 over 3 years, with 0.42 over the last year and 0.56 over 5 years.
Is IWM a good diversifier for CERS?
Only partially. A correlation of 0.59 means CERS and IWM share most of their swings. Pairing them dampens volatility somewhat, but it will not protect against a common drawdown.
What does a correlation of 0.59 mean?
On the −1 to +1 scale, 0.59 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.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/cers-vs-iwm.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/cers-vs-iwm/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: CERS correlations · IWM correlations
