This thesis consists of two independent studies. The first study works on the effect of government regulation on financial markets. The second study analyses the multitask nature of government regulation in a regionally decentralized authoritarian regime. The first study examines the influences of the 1934 US Securities and Exchange Act on stock markets. The Securities and Exchange Acts of 1933/1934 are the first nationwide public laws of financial regulation in the world. By imposing mandatory information disclosure requirements, these laws are implemented with the aims of reducing speculation and manipulation of stock prices. Subsequent financial regulations all over the world follow the principles embedded in these two laws. However, 80 years later, the effects of these laws on financial markets are still under debate and continue to have deep implications on law and financial development at a global scale. In this study I examine the impact of the 1934 Act in reducing stock idiosyncratic volatility. Monthly firm-level idiosyncratic volatility series for NYSE/AMEX listed firms in the period of 1926 - 1970 are constructed from daily CRSP stock data; voluntary disclosed accounting data from “Moody’s Manual of Investments 1934” are manually collected as a proxy of firms’ disclosure quality before the law. The comparisons of the firm-level idiosyncratic volatilities before and after the enactment of the Acts show systematic evidence indicating that the Acts significantly reduce idiosyncratic volatility. Moreover, the firms that disclose much less the key accounting information before the implementation of the Acts, have experienced more reductions in volatility and are thus more deeply affected by the Acts than others. In addition, these firms are associated with further reductions in bid-ask spreads and additional improvements in liquidity after the enactment of the Acts. My findings suggest that one of the mechanisms, through which the Acts affect the market, have been identified. The second study explores the ...