Your Brain Is Lying to You (And It's Costing You Money)
The Myth of the Rational Investor Classical finance was built on a comforting fiction: the rational actor . Someone who processes every piece of information objectively, weighs risk and reward with cold precision, and always acts in their own best interest. Efficient Market Hypothesis, CAPM, Modern Portfolio Theory — an entire discipline was constructed on this assumption. Then reality showed up. Bubbles form. Panics spread. People sell winners too early and hold losers too long. Retail investors pile into an IPO on hype alone, and institutional desks aren't immune either. If markets were truly rational, none of this should happen with the regularity it does. Behavioral finance exists because the numbers alone were never the whole story — the person reading the numbers is part of the equation too. What Behavioral Finance Actually Studies Behavioral finance sits at the intersection of psychology and economics. It doesn't throw out traditional financial theory — it ad...