A Seoul court has sentenced the chairman of South Korean conglomerate SK Group to four years in prison for embezzling millions of dollars of company money for personal investments.

Seoul Central District Court said Thursday that Chey Tae-won was guilty of embezzling 46.5 billion won ($42.7 million) from two SK Group affiliate companies, which he invested in stock futures and options. Chey had denied the charge.

SK Group is South Korea's third-largest chaebol, or family-controlled conglomerate, with telecoms and energy businesses.

The ruling comes after President-elect Park Geun-hye vowed to toughen punishment of crimes by chaebol bosses.

Chey received a suspended prison term in 2008 for accounting fraud but was later pardoned by President Lee Myung-bak.