Correlation Analysis
Biogen Inc. Common Stock vs Eli Lilly & Co.
BIIB vs LLY
-0.667
Strong inverse
When one moves up, the other tends to move down.
Biogen Inc. Common Stock
↗BIIB
Biogen is an established biopharmaceutical company focused on treatments for neurodegenerative and rare diseases. Its declining multiple sclerosis franchise is its largest revenue generator and contributed 40% of total revenue in 2025. Biogen also generates significant revenue from its CD20 collaboration agreements with Roche (19% of total in 2025), which includes oncology drugs Rituxan and Gazyva and multiple sclerosis drug Ocrevus. Biogen's newer franchises include Spinraza (spinal muscular atrophy, with partner Ionis), Leqembi (Alzheimer's disease, collabroation revenue from its partner Eisai), Skyclarys (Friedreich's ataxia, Reata), Zurzuvae (postpartum depression, Sage), and Qalsody (amyotrophic lateral sclerosis, Ionis).
Market cap 25.3B · 7,500 employees
Eli Lilly & Co.
↗LLY
Eli Lilly is a drug firm with a focus on neuroscience, cardiometabolic, cancer, and immunology. Lilly's key products include Verzenio for cancer; Mounjaro, Zepbound, Jardiance, Trulicity, Humalog, and Humulin for cardiometabolic; and Taltz and Olumiant for immunology.
Market cap 828.2B · 50,000 employees
Time Series
Relative Performance
Who Moves First
LLY leads BIIB by 6 days
LLY tends to move before BIIB.
After testing 13 timing shifts, the strongest relationship was -0.673 (they moved in opposite directions).
Do They Crash Together?
Correlation by Market Regime
How these series behave when markets are rising, falling, or diverging. A correlation that holds in drawdowns is very different from one that only works in rallies.
Both Rising
-0.002
9 periods · Return correlation when both series rose
Both Falling
+0.430
5 periods · Return correlation when both series fell
Diverging
-0.440
21 periods · Return correlation when series moved apart
R-Squared
44.4%
Share of variance in one series explained by the other.
Trend Agreement
60.2%
How often both series moved in the same direction period-to-period.
Overlap Quality
1,253
Deep shared window — 1,253 usable pairs.
Significance
p < 0.001
95% CI: [-0.696, -0.635]
Scatter
XY Regression
Pipeline
Data quality details
Pipeline
Data quality details
Pipeline Summary
1,253 paired data points survived the daily window.
Raw input
1,253
1,254
Normalized
1,253
1,254
Prepared
1,253
1,254
Aligned
1,253
1,253
Invalid removed
0
A: 0 / B: 0
Duplicates removed
0
A: 0 / B: 0
Alignment drops
1
A: 0 / B: 1
Series A
Biogen Inc. Common Stock
BIIB
Market cap 25.3B · 7,500 employees
Stock · 1,253 raw → 1,253 prepared
Series B
Eli Lilly & Co.
LLY
Market cap 828.2B · 50,000 employees
Stock · 1,254 raw → 1,254 prepared
Sign agreement
100.0%
How often both values share the same sign.
Zero crossings
5
Estimated crossover points between normalized spreads.
Slope
-3.0359
Linear regression slope.
Intercept
1247.4878
Linear regression intercept.
Related Extremes
Highest and Lowest Correlated
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