We examine performance of actively managed equity funds in Korea for the period from 2002 to 2008 and investigate if fund managers have market timing abilities. We obtain the following findings: (1) average performance of funds evaluated at net return basis(net of expenses) is statistically indistinguishable from zero; (2) average performance of funds evaluated at gross return basis(before netting expenses) exceeds benchmark market returns significantly. More importantly, when funds are grouped by their size of expenses, higher performance is matched with larger expense; (3) the regression results for decomposing positive excessive returns of large-expense funds between market timing and stock selection ability are mixed. The first two findings of the paper are consistent with the Efficient Market Hypothesis a lá Grossman and Stiglitz(1980). Concluding remarks, however, need to be reserved since sources of excessive performance of funds with large expenses are yet to be clarified.