Your worst investing enemy? You.

In the world of investing, the biggest threat to long-term wealth isn't just market volatility or economic downturns. It's you. Behavioural finance, the study of how psychology influences investor decisions, has repeatedly shown that human biases quietly and consistently undermine investment outcomes. Whether you're an amateur or a seasoned professional, your brain is wired to make systematic mistakes. Understanding these biases and designing a portfolio strategy that accounts for them may be one of the most important steps you take as an investor. The costly pull of human bias Let's start with recency bias, the tendency to overweight recent experiences while discounting long-term patterns. Data shows more than 70 per cent of mutual funds that ranked among the top 20 per cent in one year fail to maintain that position the following year. Meanwhile, nearly two-thirds of the bottom performers improve in subsequent years. Thus, chasing last year's stars is often a recipe for disappointment. Then there's naive diversification, spreading investments across too many schemes without examining overlap or correlation. Our analysis shows that a carefully selected portfolio of just five least-correlated scheme