Third-quarter operating margins of South Korea's top 100 companies topped the 10 percent mark for the first time in three years amid the local economy's recovery from the coronavirus pandemic fallout, data showed Monday.

Their average operating margin of the leading companies by sales, excluding financial and state corporations, stood at 10.74 percent in the July-September period, up 1.98 points from the prior quarter, according to the data compiled by Yonhap News and the Federation of Korean Industries (FKI).

It marks the first time for their average operating margin to surpass 10 percent since 2018, when their total operating profit soared amid a chip industry boom.

The figure refers to the ratio of operating income to sales and serves as a key barometer of a company's profitability.

Their combined sales climbed 7.8 percent on-quarter to 307.4 trillion won ($258 billion) in the three-month period with their total operating income spiking 32.2 percent to slightly over 33 trillion won.

The FKI, the lobby for South Korea's family-controlled conglomerates, said the surge in their operating margins is a testament to their rebound from the fallout of the coronavirus pandemic.

Of the total companies, 27 registered double-digit operating margins in the third quarter, with nine firms reporting negative figures.

Top shipper HMM Co. posted the largest operating margin of 57 percent for the third quarter, followed by coronavirus test-kit maker SD Biosensor with 50 percent, SK Lubricants Co. with 40 percent, LG Energy Solution Ltd. with 37 percent and chip titan SK hynix Inc. with 36 percent, according to the data. (Yonhap)