MRK vs PFE: Correlation
Measured on weekly returns over the past three years, Merck & Co. (MRK) and Pfizer (PFE) 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 MRK and PFE?
Over the past 3 years, MRK and PFE moved with a correlation of 0.45, which is moderate. Little has changed lately, as the 1-year reading of 0.45 lands near the 3-year figure. Over 5 years the correlation is 0.39, and the annualized covariance of weekly returns is 302.3 %².
By 3-year correlation, PFE places #15 of the 34 assets tracked against MRK. Correlation aside, the last 12 months split them widely, with MRK ahead by 64.2 points (+83.8% versus +19.6%). Do not treat this figure as fixed: across three years the rolling one-year correlation ranged all the way from 0.05 to 0.80.
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 PFE: side by side
| MRK (Merck & Co.) | PFE (Pfizer) | |
|---|---|---|
| 1-year return | +83.8% | +19.6% |
| 5-year return | +128.5% | -21.9% |
| Volatility (ann.) | 27.9% | 23.8% |
| Beta vs S&P 500 | 0.28 | 0.40 |
| Max drawdown (3Y) | -43.4% | -34.8% |
| Market cap | $368.9B | $159.7B |
| P/E (trailing) | 121.6 | 37.4 |
| Dividend yield | 2.17% | 6.08% |
| Sector / category | Health Care | Health Care |
Year-by-year returns
| Year | MRK | PFE |
|---|---|---|
| 2022 | +49.4% | -10.4% |
| 2023 | +1.0% | -41.3% |
| 2024 | -6.3% | -2.2% |
| 2025 | +9.8% | +0.6% |
| 2026 | +44.1% | +18.3% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are MRK and PFE good diversifiers for each other?
A fair diversifier. At 0.45, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
FAQ
What is the correlation between MRK and PFE?
As of 2026-08-27, the correlation of weekly returns between MRK and PFE is 0.45 over 3 years, 0.45 over 1 year and 0.39 over 5 years.
Is PFE a good diversifier for MRK?
A fair diversifier. At 0.45, enough of each asset's movement is its own that the pair has smoothed outcomes historically.
What does a correlation of 0.45 mean?
Correlation ranges from −1 to +1. Values near +1 mean two assets move together, near 0 that they move independently, and negative values that they tend to move in opposite directions. It measures co-movement, not performance.
Use this data
$ curl https://www.pairbook.io/api/v1/pairs/mrk-vs-pfe.json
Embed this badge (it refreshes with the data), with attribution:
[](https://www.pairbook.io/pair/mrk-vs-pfe/)
The core API is free. Terms and every endpoint in the API documentation.
Related comparisons
Hubs: MRK correlations · PFE correlations
