In this thesis, I examine the following three temporal influences on the cross-section of stock returns: disclosure and analyst regulations, the subprime credit crisis, and time-varying investor sentiment. The thesis consists of three essays.The first essay deals with the influence of regulation. Between 2000 and 2003 a series of disclosure and analyst regulations curbing abusive financial reporting and analyst behavior were enacted to strengthen the information environment of U.S. capital markets. I investigate whether these regulations benefited investors by increasing stock market efficiency. After the regulations, I find a significant reduction in short-term stock price continuation following analyst forecast revisions and past stock returns. The effect was more pronounced among higher information uncertainty firms, where I expect security valuation to be most sensitive to the regulations. Further analysis shows that analyst forecast accuracy improved in these firms, consistent with reduced mispricing being due to an improved corporate information environment following the regulations. My findings are robust to controlling for time trends, trading activity, the recent financial crisis, and changes in firms' analyst coverage status and delistings. In the second essay, I examine whether the value premium survived the recent subprime credit crisis. I find that value stocks underperformed growth stocks during the crisis, resulting in a value discount, while the value premium was significantly positive before the crisis. This is consistent with value stocks being riskier than growth stocks because they are more vulnerable during bad times. The value premium reversal during the crisis worked primarily through financially constrained firms, suggesting that the effect was due to the adverse influence of the crisis rather than confounding effects. The results are robust to controlling for common risk factors and alternative financial constraint proxies.The third essay is related to time-varying investor sentiment. Recent literature in financial economics has examined whether investor sentiment affects asset pricing. An open question is whether an investor sentiment effect reflects mispricing or risk compensation. Currently, the literature supports the former view by documenting that investor sentiment predicts realized stock returns beyond the explanatory power of state-of-the-art factor models. But, despite its popularity, estimating expected returns from realized returns has limitations. I re-examine the evidence on investor sentiment using accounting-based implied costs of capital (ICCs). I find that ICCs cannot explain the sentiment effect on stock returns. If ICCs are reliable expected return proxies, this suggests that the investor sentiment effect does not exist ex ante and confirms previous evidence that mispricing is the driving force behind the investor sentiment effect on stock returns.