The Impact of Multiple Directorships on Shareholder Value Creation: Baseline Evidence From South Africa

This study aimed to investigate the impact of multiple directorships (MDs) on shareholder value creation (SVC) for 101 non-financial companies listed in South Africa from 2013 to 2022. A quantitative quasi-experimental approach was employed to evaluate the hypotheses. Data sources included integrated annual reports, OSIRIS and Who Owns Who databases. The measures of MDs comprised the proportion of independent non-executive directors with multiple directorships (PINED_MD), dummy variables for this proportion (D_PINED_MD), and the average number of board seats held by INEDs (AVEBST_INED). SVC was measured using standard market value added (SMVA), market-to-book ratio (MTB) and Tobin’s Q (TBQ). Fixed effects models (FEM) were used to test the hypotheses. The curvilinear quadratic FEM revealed that PINED_MD exhibited an inverted U-shaped effect on SMVA and MTB, attaining maximum value when PINED_MD was between 80% and 100%. In comparison, a U-shaped effect on TBQ reached a minimum turning point when PINED ranged between 20% and 40% of the INEDs. AVEBST_INED displayed an inverted U-shaped effect on all SVC measures that attained optimal values when AVEBST_INED was 12. The statistical results suggested that MDs can enhance or diminish shareholder value, consistent with the integration of reputation and busyness hypotheses. The study highlighted the necessity of imposing limits on MDs.