The nation's top court on Thursday upheld a four-year jail sentence against the head of the country's third-largest conglomerate, SK Group, for embezzling company funds.

Chey Tae-won was convicted of embezzling 46.5 billion won ($43.6 million) from two SK Group affiliates, including top mobile carrier SK Telecom Co., and funneling the funds into personal investments in stock futures and options in 2008.

The Supreme Court rejected the 53-year-old tycoon's final appeal against a verdict handed down by two lower courts, saying that he had acted out of personal greed.

In the same ruling, the court also upheld a lower court's verdict of three years and six months in prison handed down to Chey Jae-won, the chairman's younger brother and the group's vice chairman, for conspiring with the elder Chey in the embezzlement scheme.

The ruling is unusual in a country where judges are known for being lenient to powerful tycoons. The sentence will be seen as an effort by the judiciary to break away from a long practice of giving light punishment to owners of family-run conglomerates, or chaebol, citing their importance to the national economy.

"The ruling is significant in a way that the court impartially convicted the two executives of SK Group of using affiliates as the means of their crime to fulfill greed," said a court official.

The Supreme Court agreed with an appellate court's decision to question the credibility of a key witness in the case, Kim Won-hon. Kim has been accused by Chairman Chey as the main culprit behind the massive embezzlement scheme.

The Supreme Court also sided with the Seoul High Court's judgment that Chairman Chey has not shown sincere remorse, citing his previous crime record.

The elder Chey was previously sentenced to three years behind bars in 2003 for accounting fraud and illegal stock trading. However, he was released on bail the same year.

SK Group, the third-largest conglomerate by assets after Samsung Group and Hyundai Motor Group, has more than 90 affiliates, mainly in the fields of energy and telecommunications. (Yonhap)