Stock Correlations
What It Is
Stock correlation measures how two stocks move relative to each other, ranging from perfectly positive to perfectly negative.
Why It Matters
Correlations shape diversification, portfolio risk, and asset allocation decisions.
How It Works
- Correlation of +1 → move together
- Correlation of 0 → no relationship
- Correlation of –1 → move opposite
- Influenced by sector, macro trends, and market stress
Key Components
- Covariance
- Diversification
- Systemic risk
- Market regimes
Example
During market crises, correlations often rise as investors sell risk assets simultaneously.
Key Takeaways
- Lower correlations improve diversification.
- Correlations change over time.
- They are essential for portfolio construction.