South Korean prosecutors have asked for an arrest warrant for Chung Mong-koo, head of the Hyundai motor group, on embezzlement charges.
Chung is being charged with embezzlement
He is at the centre of allegations of illegal political lobbying.
The car giant is suspected of creating a slush fund to pay politicians and officials for business favours.
Prosecutors said they also planned to indict his son, Chung Eui-sun, president of Hyundai subsidiary Kia Motors, although without detaining him.
The Hyundai group has been under investigation since March, over suspicion that it sought to buy political favours by channelling cash through third parties to figures in the government.
Prosecutors have already raided the offices of Hyundai Automotive Group - South Korea's top carmaker - and three affiliate companies, and questioned key officials about the scandal.
Two lobbyists have also been arrested on suspicion of receiving money from the company, although it is unclear whether they actually sought to pay government officials.
Multi-million slush fund
In an act of public penance and to restore confidence in the firm's activities, Mr Chung and his son have already apologised to the South Korean people over the scandal, and promised to donate their 60% stake in an affiliate company, Glovis, to charity.
But it appears that more may be required. The request for an arrest warrant came just days after Mr Chung spent about 15 hours being questioned at the Supreme Prosecutors' Office in Seoul.
Senior prosecutor Chae Dong-Wook is quoted as telling a press briefing on Thursday that Mr Chung was wanted on charges "of raising some 100 billion won ($106m) in slush funds and embezzling it".
Shares in Hyundai plunged 3% on the news that prosecutors were seeking Mr Chung's arrest, according the French news agency AFP.
Hyundai spokesman Jake Jang admitted that news of the warrant was "shocking".
"Hyundai executives are all in a panic. The absence of Chairman Chung is enormous, and its ramifications are beyond description," he told the Associated Press.