Credit ratings firm Moody's on Wednesday also lowered steelmaker POSCO's credit rating by one notch from A3 to Baa1. The latest downgrade follows Standard & Poor's on Monday, where POSCO saw its rating slip from A- to BBB+.

But POSCO pointed out that it is "the only global steelmaker that posted a two-digit operating profit rate (10.7 percent) last year." It added it still enjoys a higher credit rating than rivals like India’s Arcelor Mittal (BB+) and China's Baoshan Iron and Steel (BBB).