Abstract: In this paper, statistical knowledge and ANOVA model are used to study the weekday effect of 188 stock-oriented open-ended funds during the period between February 1st, 2016 and December 31st, 2017 from the aspect of negative return, positive return and total return respectively. The results show that the sample fund returns during the study period are different, the lowest return falls on Thursday, then Friday, Wednesday, Monday and the highest return falls on Tuesday. As a result, there is a “Thursday effect”, that is, weekly investors can effectively reduce investment costs and increase investment returns by taking Thursday as the fixed investment date.

Key words: Stock-oriented Open-end Fund, Weekly Investment, Negative Returns, Positive Returns, Total Returns, weekday effect, ANOVA model