Naver surpassed the 5 trillion won line for the first time as its total assets reached 6.8 trillion won, while SM Line Corp., a mid-sized shipper; Nexon Korea Corp., a leading online game provider; and Hoban Construction Co. were also included on the new list.

The FTC's updated list came as the watchdog revised the fair trade law last year on affiliates of large business groups. It raised the minimum asset ceiling for tighter restrictions on mutual investment and loan guarantees to 10 trillion won from 5 trillion won, and introduced the new list for mandatory filings.

The FTC said the mandatory disclosure system is aimed at encouraging big companies to do business in a more transparent manner as it altered restriction rules.

Currently, affiliates of 27 large conglomerates with assets exceeding 10 trillion won are subject to tough surveillance and barred from making equity investments among themselves or offering loan guarantees to each other.

The combined assets of the 57 companies totaled 1,842 trillion won in 2017, up 5 percent from April last year, with 32.3 trillion won in assets per business.

The largest business group is Samsung with assets of 363.2 trillion won, followed by Hyundai Motor with 218.6 trillion won and SK with 170.7 trillion won. (Yonhap)