Currently, the analysis of rhetorical moves is extensively applied to business genre conventions. This paper adopts a corpus-assisted genre approach to compare three major rhetorical moves in corpora of students' and professionals' project proposal abstracts to elicit evidence-based recommendations for the pedagogy of business communication. The findings indicate that, while overall features in the proposal abstracts written by actual business professionals and those by students of business vary quantitatively but not qualitatively, students focus more on the aim of the project, and professionals tend to evenly highlight all sides of the project and position it within the context.