This document summarizes a study that examined the relationship between excess value and excess profitability among deposit money banks in Nigeria from 1998-2007. The study used regression and correlation analyses of accounting data from 18 sampled banks. The analyses revealed a positive and statistically significant correlation, indicating a relationship between excess value and excess profitability for both diversified and standalone banks. Prior literature on the costs and benefits of corporate diversification was reviewed. The study aimed to measure this relationship for Nigerian banks and hypothesized no significant relationship, which the analyses did not support.