Investor Sentiment and Stock Market Dynamics: A Conceptual Study

Abstract

Traditional financial theory assumes that markets are efficient and investors behave rationally. However, recurring anomalies such as speculative bubbles, excess volatility, and predictable return patterns challenge this assumption. Behavioural finance addresses these deviations by incorporating psychological biases into investment decision-making. Within this framework, investor sentiment—defined as collective optimism or pessimism not fully justified by fundamental information—emerges as a key driver of market fluctuations. This conceptual study synthesizes the secondary literature to develop an integrated framework that links psychological foundations, sentiment measurement approaches, and stock market outcomes. It explains how cognitive biases such as loss aversion, overconfidence, and herd behaviour shape investor sentiment. The review further highlights how sentiment can be measured through composite indices, survey-based indicators, and market-based proxies. Existing evidence suggests that investor sentiment significantly influences short-term returns, long-term reversals, and market volatility, particularly in emerging markets. The study offers a structured foundation for future empirical research and policy development.