The ruling Democratic Party(DP) has concluded that there are reasons to call for the expulsion of Rep. Lee Choon-suak, who quit the party earlier this week amid allegations of stock trading under a borrowed name.

Speaking to reporters on Thursday, Han Dong-soo, head of the DP's ethics body, said Lee violated three of the party's standards of ethics by trading shares under his aide’s name on a mobile phone during a plenary session Monday.

The ethics body chief said Lee's action constitutes a critical misconduct as it goes against an elected official's duty of good faith, and may violate the Act on Real Name Financial Transaction and Confidentiality.

Han said the ethics body concluded that Lee also breached his duty to prevent and avoid conflict of interest as the shares he traded were related to artificial intelligence, despite his position on the administration's State Affairs Planning Committee handling AI policy.

Lee's aide, identified by the surname Cha, was also found to have violated ethics standards by allegedly lending a stock trading account under his name, with Han saying that Cha's action could be subject to an expulsion.

Although Lee left the party before the party's Supreme Council could slap a disciplinary action against him, the party regulation stipulates that the ethics body can determine the degree of action against those who quit the party in apparent attempt to avoid discipline.