The Securities and Exchange Commission (SEC) expects to announce in July the penalties, including a blacklist, for listed companies' executives found guilty of unfair securities trading, its chief says.
The watchdog is holding a public hearing on the issue that will take a few weeks to conclude before the official announcement is made, SEC secretary-general Rapee Sucharitakul said.
The new penalties are also expected to take effect in July, he said.
The bid to toughen the penalties for unfair trading comes after three top executives of the 7-Eleven convenience store chain operator CP All Plc and an executive of True Corporation Plc were fined a combined 33.3 million baht by the SEC for using inside information for their own benefit.
CP All executive chairman Korsak Chairasmisak, vice-chairman Piyawat Titasattavorakul, vice-chairman Pittaya Jearavisitkul and True vice-chairman Athueck Asvanund used insider knowledge to buy shares of cash-and-carry giant Siam Makro Plc ahead of CP All's announcement it would buy out Makro at an above-market price.
The case prompted public calls for those involved in insider trading to resign, while mutual fund companies decided to avoid any additional investment in CP All based on concerns about corporate governance.
The company's board of directors, however, decided to keep all the executives in place and established a new committee to oversee its corporate governance in a bid to prevent the problem from happening in the future.
Even though the SEC has authority to ban securities and mutual fund companies' executives from holding management positions in any securities-related company if they are found guilty, the current punishment does not extend to executives of listed companies.
Mr Rapee said listed companies' executives who violate laws and are fined by the regulator or convicted by a court will not be allowed to keep their positions.
The blacklist period depends on the degree of wrongdoing and damage to the company and other stakeholders, he said without elaborating on details.