• Audit committees;
  • board of directors;
  • agency theory

The goal of this paper is to determine the factors that explain voluntary improvements in audit committee activity, independence and financial expertise, both individually and jointly, within a corporate governance environment other than those used in previous works. These audit committee characteristics have been selected because previous authors have found that these attributes improve the effectiveness of this monitoring committee. The findings included a relatively high level of the proxies of audit committee effectiveness for those companies which display the best practices in terms of their board of directors' independence and activities. At the same time, we observed a non-linear relationship of substitution among internal control mechanisms, management ownership and audit committee characteristics.