LG Group Chairman Koo Kwang-mo on Thursday lost a lawsuit he filed together with his family members to recoup part of the near 1 trillion won ($735.7 billion) in inheritance taxes imposed following the death of former Chairman Koo Bon-moon.

After the former chairman's death in 2018, a combined 990 billion won in taxes were imposed on Koo Kwang-mo and other members of the owning family for their inheritance worth about 2 trillion won that included an 11.28 percent share in LG Corp., the holding company of LG Group, one of South Korea's biggest family-controlled conglomerates.

Koo, along with his mother and two sisters, has since filed a lawsuit against the chief of the National Tax Service's Yongsan district office, contesting what they claim to be an excessive tax imposition and demanding the cancellation of part of it.

The Seoul Administrative Court ruled against the family, without elaborating on the reasoning behind the decision.

The Koo family demanded a recalculation of the value of the inherited 1.12 percent unlisted share in LG CNS, an IT service management firm, in the suit. If the court had ruled in favor of the family, they would have recouped 1 billion won out of the taxes paid.

Koo's side had argued that the value of the unlisted CNS share was calculated based on trades between small shareholders and the calculated figure can differ from the actual market prices.

Currently, Koo is facing a separate suit from his mother and sisters, who are demanding a redivision of the inheritance.

Koo inherited an 8.76 percent share in LG Corp., becoming the biggest shareholder, while his two sisters were given shares of 2.01 percent and 0.51 percent, respectively, along with the late chairman's personal assets. (Yonhap)