This study investigates the moderating effect of firm age on the relationship between ownership structure and financial performance of listed financial service firms in Nigeria, using Tobin’s Q as a proxy of financial performance. The study adopted ex-post facto research design and utilized secondary panel data obtained from the audited annual reports of 44 listed financial service firms covering the period 2015–2024, yielding 440 firm-year observations. Ownership structure was measured using institutional ownership, managerial ownership, foreign ownership and ownership concentration, while firm age served as the moderating variable. The data were analyzed using panel regression techniques and the Hausman specification test indicated that the Random Effects estimator was the most appropriate for all three models. The findings of the study showed that institutional ownership has a positive and significant effect on financial. Foreign ownership also has a significant positive influence on financial performance, while managerial ownership is statistically insignificant, indicating weak alignment between managerial shareholding and market valuation. Ownership concentration exhibited mixed but generally positive effects. The moderation analysis reveals that firm age significantly strengthens the relationship between institutional ownership and financial performance and also between ownership concentration and financial performance but does not significantly moderate the effects of managerial ownership and foreign ownership. The study concludes that ownership structure and firm age jointly influence financial performance in Nigeria’s financial services sector. The study recommends stronger institutional participation, increased foreign investor involvement, and age-sensitive governance practices to enhance market performance and strengthen firm financial performance.

Keywords: ownership structure, financial performance, firm age, financial services firms in Nigeria.