This study examines how banking market concentration relates to accounting and market-based performance and whether financial slack conditions these relationships. An unbalanced panel of 818 Indonesian non-financial listed firms produced 6,537 firm-year observations for 2015–2025. Firm fixed-effects models with clustered standard errors show that concentration is negatively associated with ROA and ROE but positively associated with Tobin’s Q. The concentration–slack interaction is negative for ROA and Tobin’s Q, but insignificant for ROE. Robustness estimates support the ROA interaction, while the valuation interaction is estimator-sensitive.
Copyrights © 2026