Students who transfer between institutions of higher education often experience "transfer shock", a temporary decrease in academic performance (GPA) hypothesized to be due to changes in academic expectations between institutions. This study used university institutional records to explore the magnitude of transfer shock; the factors contributing to the GPA effects of transfer shock; and the impact of shock and other student characteristics on important academic outcomes, including persistence in a STEM major and baccalaureate degree. We found that STEM majors and students transferring from two-year institutions experienced the largest degree of transfer shock and that shock was a significant predictor of change of major. Most intriguingly, we found interaction effects where shock had a greater impact on institutional retention for two-year transfers and science or mathematics majors. Implications for future research and academic policies and interventions are discussed.