MRK vs SPY: Correlation
Merck & Co. (MRK) and SPDR S&P 500 ETF Trust (SPY) show a weak relationship: their 3-year correlation of weekly returns is 0.14.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are MRK and SPY?
Across a 3-year window, the weekly returns of MRK and SPY correlate at 0.14, weak. The link has loosened recently: the 1-year correlation (-0.11) runs below the 3-year figure (0.14). Stretching to 5 years gives 0.12, with an annualized covariance of 57.5 %².
By 3-year correlation, SPY places #23 of the 34 assets tracked against MRK. The last year tells two different stories: MRK led by 63.2 percentage points, +83.8% for MRK against +20.6% for SPY. This link changes with the market regime, having swung between -0.11 and 0.41 on a rolling one-year basis. Note the risk asymmetry: MRK runs 1.9 times the annualized volatility of the other leg, so equal-weighting the two is not an equal-risk position.
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.
MRK vs SPY: side by side
| MRK (Merck & Co.) | SPY (SPDR S&P 500 ETF Trust) | |
|---|---|---|
| 1-year return | +83.8% | +20.6% |
| 5-year return | +128.5% | +82.4% |
| Volatility (ann.) | 27.9% | 14.5% |
| Beta vs S&P 500 | 0.28 | 1.00 |
| Max drawdown (3Y) | -43.4% | -18.8% |
| Market cap | $368.9B | – |
| P/E (trailing) | 121.6 | – |
| Dividend yield | 2.17% | 1.01% |
| Expense ratio | – | 0.09% |
| Assets under management | – | $795.3B |
| Sector / category | Health Care | 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 | MRK | SPY |
|---|---|---|
| 2022 | +49.4% | -18.2% |
| 2023 | +1.0% | +26.2% |
| 2024 | -6.3% | +24.9% |
| 2025 | +9.8% | +17.7% |
| 2026 | +44.1% | +13.7% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Fund exposure
MRK represents 0.57% of SPY's portfolio, so part of any move in SPY is MRK itself, and the correlation between them is partly mechanical.
Are MRK and SPY good diversifiers for each other?
Yes. With a correlation of 0.14, MRK and SPY have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
FAQ
What is the correlation between MRK and SPY?
The MRK/SPY correlation stands at 0.14 on a 3-year window (1 year: -0.11, 5 years: 0.12), computed from weekly returns as of 2026-08-27.
Is SPY a good diversifier for MRK?
Yes. With a correlation of 0.14, MRK and SPY have moved largely independently, which makes them a genuinely diversifying pair by historical standards.
What does a correlation of 0.14 mean?
On the −1 to +1 scale, 0.14 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: MRK correlations · SPY correlations
