A special counsel team investigating former first lady Kim Keon-hee summoned sitting or former heads of four corporations on Monday over allegations that Kim's aide secured investments from the businesses under suspicious circumstances.

The team notified Kakao Corporation founder Kim Beom-su, HS Hyosung Vice Chairman Cho Hyun-sang, former Korea Securities Finance Corporation CEO Yoon Chang-ho, and former Daou Kiwoom Group Chairman Kim Ik-rae to appear for questioning as witnesses on Thursday.

The former first lady's aide, identified by the surname Kim, is suspected of securing investments worth 18 billion won, or around 13 million U.S. dollars, from the businesses in 2023, despite their car rental company posting cumulative losses of 34-point-six billion won.

Last Tuesday, the Seoul Central District Court dismissed the team's request for a search and seizure warrant which indicated breach of duty charges against the four companies, explaining that such allegations are not subject to the special prosecutor investigation.