ENS vs IWM: Correlation
How closely do EnerSys (ENS) and iShares Russell 2000 ETF (IWM) trade together? Their weekly returns over three years give a correlation of 0.58, which is moderate.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are ENS and IWM?
Across a 3-year window, the weekly returns of ENS and IWM correlate at 0.58, moderate. The link has loosened recently: the 1-year correlation (0.36) runs below the 3-year figure (0.58). Stretching to 5 years gives 0.65, with an annualized covariance of 347.4 %².
In ENS's tracked universe of 11 assets, IWM sits right near the top at #3. Their recent paths diverged sharply: over the last 12 months ENS outperformed by 59.5 percentage points (+87.9% for ENS against +28.4% for IWM). One caveat on sizing: ENS is 1.5 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.
ENS vs IWM: side by side
| ENS (EnerSys) | IWM (iShares Russell 2000 ETF) | |
|---|---|---|
| 1-year return | +87.9% | +28.4% |
| 5-year return | +131.9% | +41.5% |
| Volatility (ann.) | 30.1% | 19.8% |
| Beta vs S&P 500 | 1.09 | 1.06 |
| Max drawdown (3Y) | -28.2% | -27.5% |
| Market cap | $6.9B | – |
| P/E (trailing) | 20.7 | – |
| Dividend yield | 0.54% | 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 | ENS | IWM |
|---|---|---|
| 2022 | -5.6% | -20.5% |
| 2023 | +37.9% | +16.8% |
| 2024 | -7.6% | +11.4% |
| 2025 | +60.3% | +12.7% |
| 2026 | +30.5% | +22.3% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
Keep in mind that IWM holds ENS at a 0.23% weight, which makes a slice of this correlation mechanical rather than coincidental.
Are ENS and IWM good diversifiers for each other?
Only partially. A correlation of 0.58 means ENS 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 ENS and IWM?
As of 2026-08-27, the correlation of weekly returns between ENS and IWM is 0.58 over 3 years, 0.36 over 1 year and 0.65 over 5 years.
Is IWM a good diversifier for ENS?
Only partially. A correlation of 0.58 means ENS 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 0.58 mean?
A reading of 0.58 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/ens-vs-iwm.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/ens-vs-iwm/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: ENS correlations · IWM correlations
