Most of South Korea's 10 largest conglomerates are estimated to have suffered a drop in their earnings in the first half of the year from a year earlier amid economic woes and declining demand in advanced economies, data showed Monday.

With the exception of Samsung and Hyundai Motor Group, eight of the top 10 conglomerates saw their first-half business results worsen, according to data from financial provider FnGuide.

Eleven affiliates of Samsung Group are expected to report a combined operating income of 14.7 trillion won for the January-June period, up 65.2 percent from a year earlier.

Their sales are forecast to have jumped 22.7 percent on-year to 133 trillion won in the first half, with their net profit reaching 12.2 trillion won, up 54.1 percent.

The sharp growth was projected to be mostly powered by key affiliate Samsung Electronics, the country's top company in terms of sales and market capitalization.

Samsung Electronics' second-quarter sales are expected to reach 50.2 trillion won, compared with 45.3 trillion won the previous quarter.

Hyundai Motor Group fared reasonably well given the business environment, with the combined operating income of seven affiliates expected to have risen 14.2 percent on-year to 9.9 trillion won in the first half.

Its key affiliates -- Hyundai Motor Co. and Kia Motors Corp. -- are expected to see their combined sales reach 34.8 trillion won in the second quarter, up from 32 trillion won the previous quarter.

But other conglomerates are likely to see their earnings plunge sharply in the first half as they failed to weather economic uncertainties.

The net profits of 10 LG affiliates are expected to have slipped 2.3 percent to 2.2 trillion won in the first half.

Its key affiliate LG Electronics Inc. is expected to have stayed in the black on the back of growth in their smartphone business, but LG Chem and other affiliates are likely to have suffered from the economic woes.

SK Group is also expected to report smaller net profits and operating income in the first half mainly due to a slump in its chemical and petrochemical businesses.

Economists said South Korean conglomerates are unlikely to see their earnings improve down the road.

"Eurozone woes are likely to last for the time being, which will continue to put downward pressure on corporate earnings," said Kim Hak-kyun, an analyst at KDB Daewooo Securities. (Yonhap News)