Portfolio Diversification and Correlation: The Hidden Driver
“Diversification” sounds like a simple promise. Buy more than one asset, and you reduce risk. In practice, that promise only holds when the pieces of your portfolio do not move together. The hidden driver behind a diversified portfolio is correlation, the tendency for holdings to rise and fall at the same time. Most investors learn the idea in theory, then run straight into the part that hurts: they own “diversified” things that still behave like the same trade. When mar