This thesis is an attempt to advance our understanding of investor behaviour in one of the world's largest markets, i.e. the mutual fund industry. It consists of three essays that answer the following questions: Does investor fund-selection ability explain the impressive growth of the U.K. mutual fund industry? Does the behaviour of U.S. mutual fund investors vary across the business cycle? And, how do investors react to U.S. mutual fund name changes? The first essay explores the role of investor fund-selection ability in explaining the growth of the mutual fund industry given that previous studies find that mutual funds underperform their benchmarks on average. I examine such ability in the context of the remarkable growth experienced by U.K. mutual funds during the decade of 2000-2010. Using three alternative measures of selection ability and two for performance measurement, I find that fund-selection ability is explained away by the momentum factor due to investors naively chasing recent winners. In addition, this essay is the first to examine the impact of fund visibility on selection ability. I find that fund visibility is an important factor in the investment decision-making process, and one that fund managers can potentially manipulate to their advantage. The second essay is motivated by recent findings that benchmark-adjusted returns to the fund industry are positive in periods of economic contractions. Previous literature is silent on investor behaviour in the face of superior average returns. This essay fills the gap in literature by examining investor's fund-selection ability across the business cycle. I examine U.S. fund data from 1970-2011 and find that while genuine selection ability does not exist in any period, investors do behave differently across the business cycle. Specifically, investors no longer chase recent winners during contractions, despite no change in fund performance consistency. Instead, I find that investors are more concerned about controlling their risk exposure, especially to the market, during periods of economic downturn. The third essay examines investor reactions to U.S. mutual fund name changes, following the adoption of a new SEC ruling in 2001 to curtail misleading names. We uncover striking evidence that funds continue to undertake cosmetic name changes, and that such changes appear to mislead investors. I find that investors react more positively to cosmetic name changes than non-cosmetic ones. This result is not driven by marketing efforts. Instead, further examination reveals that this arises because cosmetic name changes frequently include industry 'buzzwords' in the new name, a tactic that is rewarded with higher flows to such funds. I also find that additional name changes by a fund continue to attract significant flows, although the magnitude of the flows decreases over each successive event. This essay provides compelling evidence in favour of investor irrationality and has implications for both practitioners and academics.