This study examined the effect of corporate governance variables of board independence, institutional ownership, managerial ownership, board size, and director expertise on the market reaction to seasoned equity offering (SEO) announcements by firms in the Nigerian stock market. The event study methodology was employed, and abnormal returns were computed using the market model. A total of 62 announcements by 38 firms listed on the Nigerian stock exchange from 1st January 2006 to 31st December 2016 were included in the analysis. The study recorded significant positive cumulative abnormal returns before and after the announcement day, and a significant negative cumulative abnormal return upon the announcement day of SEOs. Similarly, significant positive cumulative abnormal returns were recorded six months before the SEO announcement day and negative significant cumulative abnormal returns six, twelve, and twenty-four months after the announcements. Furthermore, there were significant cumulative abnormal returns upon SEO announcements for all the proxies of corporate governance assessed by the study. The implication of the findings of negative significant cumulative abnormal returns on the day of the announcement and beyond was consistent with previous arguments that firms issuing SEOs earn negative abnormal returns on the day of the announcement was the result of the information asymmetry between managers and investors. By contrast, the significant cumulative abnormal returns based on corporate governance suggested that corporate governance significantly impacted on SEO announcement returns in Nigeria. These findings suggest that policy makers should pay more attention to directors’ expertise, institutional ownership, board independence, and board size, as our results showed that investors might view them as dependable pointers of positive corporate information for the market, thus guaranteeing the best use of SEO proceeds.

The objective of this study is to implement Analysis of Moment Structure (AMOS) at the same time analysing the power of corporate governance on Post-Seasoned Equity Offerings (SEO's) performance as well as in determining whether agency costs exist as a mediating variable between them. We conjecture that the mediating function of agency costs reduction is fundamental to the causal relationship between corporate governance and Post-SEO underperformance. Failure to tackle agency costs as a mediating variable may perhaps be one reason for the inconclusive findings in the allied literature. This study intends to focus on an SEO sample, for the reason that it is essential to evaluate how better corporate governance mechanisms can enhance SEO performance by estimating the relationship between different variables. To achieve this, the study will apply the approach and analyse SEOs in Nigeria from 2005-2015.