BSX vs KELYB: Correlation
Boston Scientific (BSX) and Kelly Services, Inc. (KELYB) show a negative relationship: their 3-year correlation of weekly returns is -0.33.
Data as of 2026-08-27 · refreshed every trading day · weekly returns · methodology
How correlated are BSX and KELYB?
Across a 3-year window, the weekly returns of BSX and KELYB correlate at -0.33, negative, meaning they tend to move in opposite directions. Lately the two have drifted apart, with the 1-year correlation at -0.45 versus -0.33 over 3 years. Stretching to 5 years gives -0.18, with an annualized covariance of -546.7 %².
Among the 33 assets we track against BSX, KELYB sits near the bottom by co-movement, at rank #32. Their recent paths diverged sharply: over the last 12 months KELYB outperformed by 118.7 percentage points (-55.9% for BSX against +62.8% for KELYB). Risk is not evenly split, since KELYB carries 2.2 times the volatility of the other side.
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.
BSX vs KELYB: side by side
| BSX (Boston Scientific) | KELYB (Kelly Services, Inc.) | |
|---|---|---|
| 1-year return | -55.9% | +62.8% |
| 5-year return | +4.1% | +26.3% |
| Volatility (ann.) | 27.6% | 60.8% |
| Beta vs S&P 500 | 0.72 | 0.40 |
| Max drawdown (3Y) | -60.6% | -66.9% |
| Market cap | $67.6B | $0.8B |
| P/E (trailing) | 19.5 | – |
| Dividend yield | 0.00% | 1.38% |
| Sector / category | Health Care | US Listed |
Year-by-year returns
| Year | BSX | KELYB |
|---|---|---|
| 2022 | +8.9% | +3.1% |
| 2023 | +24.9% | +27.5% |
| 2024 | +54.5% | -34.7% |
| 2025 | +6.8% | -35.9% |
| 2026 | -51.1% | +170.6% |
Calendar-year price returns; the current year is year-to-date as of the data date above.
Are BSX and KELYB good diversifiers for each other?
Yes: at -0.33, the two have gone their own ways historically, which is what genuine diversification looks like.
FAQ
What is the correlation between BSX and KELYB?
As of 2026-08-27, the correlation of weekly returns between BSX and KELYB is -0.33 over 3 years, -0.45 over 1 year and -0.18 over 5 years.
Is KELYB a good diversifier for BSX?
Yes: at -0.33, the two have gone their own ways historically, which is what genuine diversification looks like.
What does a correlation of -0.33 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/bsx-vs-kelyb.json
Drop this badge in a README or notebook; it updates with the data:
[](https://www.pairbook.io/pair/bsx-vs-kelyb/)
No key needed, free to use. Full endpoint list in the API documentation.
Related comparisons
Hubs: BSX correlations · KELYB correlations
