In a report submitted to Rep. Park Chan-dae of the ruling Democratic Party, the Financial Supervisory Service said it has found that Lee kept money in 32 more "borrowed-name" accounts.
Last week, police named Lee as a suspect in a tax evasion case, accusing him of managing 400 billion won in 260 newly found accounts held by executives at Samsung.
Lee, who has been hospitalized after suffering a heart attack in 2014, could not be questioned and the case was referred to prosecutors, police said.
The public scrutiny of Lee's assets again put the spotlight on the 2008 investigation in which Lee was convicted on charges of tax evasion and breach of trust.
|Samsung Group`s chairman Lee Kun-hee (Yonhap)|
At that time, prosecutors found that Lee owned assets, believed to be inherited from his father and the founder of Samsung Group, Lee Byung-chul, in about 1,200 accounts held by his lieutenants.
Of the total 1,489 borrowed-name accounts, most were believed to have been opened at Samsung Securities, the brokerage unit of Samsung Group, the lawmaker said.
A 1993 law requires South Koreans to open bank or other financial accounts using their real names.
Authorities can levy taxes on 99 percent of the interest and dividend income earned from "non real-name assets."
Meanwhile, the Ministry of Government Legislation clarified that the government can levy a fine against Lee for managing funds in borrowed-name accounts.
Previously, financial authorities had said they could impose taxes on Lee's funds in such accounts, but asked the ministry to clarify whether Lee could be fined for allegedly violating the 1993 law.
In line with the ministry's clarification, the Financial Services Commission said it will set up a task force with tax authorities to discuss follow-up measures. (Yonhap)