RMBS vs SPY: Correlation
Measured on weekly returns over the past three years, Rambus, Inc. (RMBS) and SPDR S&P 500 ETF Trust (SPY) carry a correlation of 0.54, a moderate link.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are RMBS and SPY?
On 3 years of weekly data the RMBS/SPY correlation comes out at 0.54, moderate. Recent behaviour matches the longer record: 0.48 over 1 year against 0.54 over 3. The 5-year figure is 0.51, and annualized covariance runs at 463.2 %².
Among the 12 assets we track against RMBS, SPY ranks #7 by 3-year correlation. Their 12-month results are close: +21.4% for RMBS against +20.6% for SPY. One caveat on sizing: RMBS is 4.1 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.
RMBS vs SPY: side by side
| RMBS (Rambus, Inc.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +21.4% | +20.6% |
| 5-year return | +269.6% | +82.4% |
| Volatility (ann.) | 59.1% | 14.5% |
| Beta vs S&P 500 | 2.22 | 1.00 |
| Max drawdown (3Y) | -51.5% | -18.8% |
| Market cap | $9.9B | – |
| P/E (trailing) | 41.4 | – |
| 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 | RMBS | SPY |
|---|---|---|
| 2022 | +21.9% | -18.2% |
| 2023 | +90.5% | +26.2% |
| 2024 | -22.5% | +24.9% |
| 2025 | +73.8% | +17.7% |
| 2026 | -0.8% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are RMBS and SPY good diversifiers for each other?
Somewhat, no more. With 0.54 correlation, most large moves hit both names, and the diversification benefit stays modest.
FAQ
What is the correlation between RMBS and SPY?
Using weekly returns as of 2026-08-27: 0.54 over 3 years, with 0.48 over the last year and 0.51 over 5 years.
Is SPY a good diversifier for RMBS?
Somewhat, no more. With 0.54 correlation, most large moves hit both names, and the diversification benefit stays modest.
What does a correlation of 0.54 mean?
A reading of 0.54 sits on a scale from −1 (opposite moves) through 0 (unrelated) to +1 (identical moves). Correlation captures direction, not magnitude or performance.
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Related comparisons
Hubs: RMBS correlations · SPY correlations
