This study examines the evolution of the impact of e-business technology on operational competence and profitability using a panel dataset of 154 Spanish firms. We find that: (1) E-business technology has a positive effect on operational competence that decreases over time; and (2) the firm's proficiency in exploiting a portfolio of operational capabilities has a positive impact on profitability that becomes more significant over time. The findings provide some insights on how the initial and subsequent IT investments affect operational competence and profitability over time. This study illustrates methodologically how to perform a partial least squares estimation using panel data.