In this dissertation, I investigate whether corporate governance affects the negative association between investment and future excess returns. Shareholders are concerned with the effectiveness of the firm's governance regime as a tool to reduce agency costs. In the absence of strong control over firm assets, managers may choose to invest in value-decreasing projects. The probability that managers select value-decreasing projects is an increasing (decreasing) function in investment activity (governance regime). At the time of investment, the capital market prices expected returns to the investment activity conditioned on the governance regime in place. This study examines future risk-adjusted returns to investment activities conditioned on low and high governance regimes. If the market correctly prices the governance environment and the expected returns to expenditures at time t, there should be no future risk-adjusted returns to either governance or expenditure information. I find that for firms with low external monitoring, and separately, for firms with high shareholder rights, lower (higher) investment activity results in positive (negative) future risk-adjusted returns. Implementing a trading strategy which holds low investment firms and shorts high investment firms results in 7.1% and 5.6% annual risk-adjusted returns when conditioned on low institutional holdings and high shareholder right, respectively. This study also provides preliminary evidence that outside blockholder and activist ownership is effective in mitigating the negative association between investment activity and future excess returns through the shareholder rights mechanism. Finally, I provide evidence that the diversification discount associated with multi-segment firms is generally invariant to investment activity levels.