A local credit appraiser has downgraded its ratings of four South Korean shipbuilders undergoing corporate restructuring. 

The Korea Ratings said Thursday it lowered the rating on the no-warranty bonds of Hyundai Heavy Industries from A+ to A and downgraded that of Hyundai Mipo Dockyard from A to A-.

The credit rating of Daewoo Shipbuilding and Marine Engineering(DSME)’s was revised downward to BB from BB+, and that of Samsung Heavy Industries was lowered by two notches to A- from A+.

Korea Ratings researcher Kim Bong-gyun said the operating profits of the four shipbuilders have significantly dwindled and the companies altogether are going through increasing risks and fluctuating performances.

He attributed Samsung Heavy Industries' drastic fall in the ratings scale to its failure to obtain any order this year and fewer remaining contracts for the company than its rivals.