Scandal at SK Global triggered the inquiry

The Fair Trade Commission (FTC) slapped fines totalling 31.5bn won ($27.2m; �16.4m) on a list of South Korea's top firms.

The bulk of that was a single fine of nearly 29m won, imposed on ports-to-telecoms conglomerate SK Group.

The FTC also penalised electronics giants Samsung and LG Group, Hyundai Group, Hyundai Motors and shipbuilder Hyundai Heavy Industries.

Clean-up

The FTC has been investigating false accounting at the country's conglomerates, or chaebols, as part of an anti-corruption drive launched by left-wing President Roh Moo-hyun.

Economists say that South Korea's big firms are notoriously opaque as they consist of complex webs of cross-holdings.

They say inefficient units are often supported by the practice of booking internal transactions as sales when goods are moved within the group, or by hiding debt.

SK Group confessed to 1.5 trillion won hole in the accounts of one of its subsidiaries, SK Global, earlier this year, triggering the FTC investigation.

SK Global was eventually put into receivership while its creditors haggled over how to recover their money.

Getting better

The FTC said that chaebols have made an effort to clean up their financial practices.

"As a whole, the business groups have made efforts to correct unfair internal transactions although some of them were still engaged in old practices," said FTC investigator Jang Hang-Suk.

The FTC estimated that chaebols carried out 90bn won of illegal internal transactions this year compared to 126.2bn won three years ago.

SK Group faces other scandals. Chey Tae-won, the head of the group's founding family, was sentenced to three years in jail for financial crimes in June 2003, and faces investigations into accounting fraud and illegal share trading.