The main subjective of this dissertation is to analyze three issues of current interest in financial economics. Chapter 2 shows that the presence of the initial short position will give traders an incentive to manipulate by buying less or selling more. When the initial short position is not revealed, this distortion will mislead the firm through the performance of the stock in the financial market. In this circumstance, the firm may mistakenly reject some good projects due to the information asymmetry. After the revealing of the initial short position, the information asymmetry could be eliminated, and thus improve the financial market\u27s efficiency potentially. Chapter 3 studies how strategic risk among investors can help explain both un...