IRM vs SPY: Correlation
Measured on weekly returns over the past three years, Iron Mountain (IRM) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.45, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are IRM and SPY?
On 3 years of weekly data the IRM/SPY correlation comes out at 0.45, moderate. Lately the two have drifted apart, with the 1-year correlation at 0.25 versus 0.45 over 3 years. The 5-year figure is 0.54, and annualized covariance runs at 200.6 %².
By 3-year correlation, SPY places #19 of the 31 assets tracked against IRM. The last year tells two different stories: IRM led by 17.5 percentage points, +38.1% for IRM against +20.6% for SPY. The relationship is regime-dependent: the rolling one-year correlation swung between 0.23 and 0.78 over the past three years, so this pair behaves very differently depending on the market environment. One caveat on sizing: IRM is 2.1 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.
IRM vs SPY: side by side
| IRM (Iron Mountain) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +38.1% | +20.6% |
| 5-year return | +219.3% | +82.4% |
| Volatility (ann.) | 30.8% | 14.5% |
| Beta vs S&P 500 | 0.96 | 1.00 |
| Max drawdown (3Y) | -39.0% | -18.8% |
| Market cap | $36.5B | – |
| P/E (trailing) | 86.4 | – |
| Dividend yield | 2.78% | 1.01% |
| Expense ratio | – | 0.09% |
| Assets under management | – | $795.3B |
| Sector / category | Real Estate | 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 | IRM | SPY |
|---|---|---|
| 2022 | -0.1% | -18.2% |
| 2023 | +46.5% | +26.2% |
| 2024 | +54.5% | +24.9% |
| 2025 | -18.2% | +17.7% |
| 2026 | +50.1% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
A structural note: 0.05% of SPY is IRM itself, so the fund partly moves with the stock by construction.
Are IRM and SPY good diversifiers for each other?
Reasonably. At 0.45, IRM and SPY keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
FAQ
What is the correlation between IRM and SPY?
As of 2026-08-27, the correlation of weekly returns between IRM and SPY is 0.45 over 3 years, 0.25 over 1 year and 0.54 over 5 years.
Is SPY a good diversifier for IRM?
Reasonably. At 0.45, IRM and SPY keep a meaningful degree of independence, and combining them has historically reduced portfolio volatility.
What does a correlation of 0.45 mean?
On the −1 to +1 scale, 0.45 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: IRM correlations · SPY correlations
