Correlations, PCA, Sectors, MST Network, Random Matrix Theory, Entropy Map, Market State, State Timeline
Correlation Heatmap — shows how much each stock moves together with every other stock.
Think of it like a friendship chart. If two stocks are best friends (bright green, close to +1), they go up and down together. If they're enemies (red, close to -1), one goes up when the other goes down. If they don't care about each other (dark/neutral, near 0), they do their own thing.
Why it matters: If all your stocks are best friends (highly correlated), your portfolio has no real diversification — they'll all crash at the same time. You want a mix of friends, enemies, and loners.