Moody's Investors Service said Wednesday that South Korean nonfinancial firms' credit ratings will remain vulnerable to shocks caused by the prolonged coronavirus crisis.

More than half of the rated Korean nonfinancial companies posted weak results in the January-June period compared to a year earlier. With the wide spread of the COVID-19 pandemic weakening business activity, negative rating actions will likely outnumber positive ones over the next 12 months, Moody's said in a statement.

"In particular, companies in cyclical sectors such as refining, chemical, steel and auto were more strongly impacted, with many reporting weaker profitability because of lower sales volumes or narrowing product spreads," the statement said.

An economic recovery is underway, but it remains tenuous and will be closely tied to containment of the coronavirus, it said.

"A recent spike in new coronavirus cases in Korea has shown that continued containment will be difficult before an effective vaccine is available," Moody's added. 

Out of the 26 private-sector nonfinancial companies that Moody's rates, 15 reported credit-negative results in the first half.

The 26 firms do not include unlisted government-related issuers. (Yonhap)