In this article, the author compares the sizes, dates of establishment, and targets of investment of mutual funds collected prior to and in the aftermath of the 2007 global financial crisis. The samples taken are funds that have existed for over five years and less than five years in 2006 and 2008, respectively. The author uses the Translog Cost Function Model to determine the existence of economies of scale in terms of magnitude and expenses of mutual funds in Taiwan. The study reveals that most mutual funds prior to the financial crisis had economies of scale, whereas such economies of scale are less significant in mutual funds existing for less than five years. Empirical results also show that fund costs have economies of scale. Thus, when choosing mutual funds, investors are advised to select the older and bigger ones. In the aftermath of some bearish events, investors should be cautious with newly established funds.