All companies listed on the benchmark KOSPI will face tougher disclosure requirements on boardroom changes and major corporate transactions under new rules designed to give shareholders greater oversight of corporate governance, financial authorities said Thursday. The changes, announced by the Financial Services Commission and the Korea Exchange, expand the information companies must provide in their annual corporate governance reports. The move comes after the reporting requirement was extended to all 826 KOSPI-listed companies this year. One focus is on preventing companies from circumventing the revised Commercial Act that is designed to give minority shareholders a greater say in board appointments. Under the law, listed companies with assets of at least 2 trillion won ($1.49 billion) must incorporate cumulative voting, which allows shareholders to pool their votes behind a particular director candidate, improving the chances of minority shareholders electing a representative to the board. Some companies, however, have sought to avoid the rule by shrinking their boards or changing d