In this article, the author analyzes the intertemporal consistency of high school grades as predictors of the academic performance of business administration students over a 2-year period by using data from a university in Germany. This study shows how students' average high school grades and a range of other factors are regressed on the students' grade performance at regular half-year intervals during their participation in the program. The author applies a bootstrapping procedure to analyze changes in the regression estimators over time and finds that the magnitude of the coefficients on high school grades decreases over the 2-year period, and this decline is statistically significant. Nevertheless, high-school grades remain the most important predictors of the students' performance throughout the period studied here. (Contains 4 tables.)