Public Information Manipulation in the Financial Market

Which factor might shape investor's sentiment in the financial market? We answer this question by introducing information manipulation into the micro-structure of a financial market. In our model, an insider inflates the fundamental to boost the equilibrium market price. Because the manipulation cost is private information, the investors treat the manipulation as a noisy signal, or rather, sentiment. The manipulation turns out to be a linear combination of fundamental and manipulation cost. The equilibrium level of manipulation decreases with market supply elasticity and transparency. Overall, our theory suggests insider's manipulation as a possible source of market sentiment.