South Korean brokerage houses have trimmed their fourth-quarter earnings forecasts for major listed firms due to slowing exports growth and weak domestic demand, a market tracker said Monday.

As of Friday, local securities companies expect 121 companies listed on the main stock market to chalk up a combined operating income of 44.1 trillion won ($39 billion) for the October-December quarter, according to FnGuide.

The forecast is up 15.5 percent from their operating profit a year earlier but down 3.8 percent from a projection made at the end of September.

As of the end of June, those companies were estimated to register a total operating income of 46.8 trillion won for the current quarter.

The 121 companies cover businesses for which three or more local securities companies have put forward operating income forecasts.

Ninety-one business concerns, or 75.2 percent of the total, have suffered downgrades in their earnings forecasts for the last quarter.

The downgrade was attributed mainly to a slowdown in growth of South Korea's exports and stubbornly anemic spending by local consumers. Given those factors, analysts said it is difficult to expect an upgrade in the market estimate of earnings by major listed companies.

"Securities companies have revised down their earnings outlooks for major listed companies in the second half," said Park Hee-jung, an analyst at Kiwoom Securities. "Earnings upgrades are not in the cards in light of slowing exports and sluggish domestic demand."

In addition, companies usually tend to report a large amount of unexpected expenses during the fourth quarter of every year, the analyst added.

According to the Korea Exchange, the combined operating income of 534 major listed firms came to 130 trillion won in the first three quarters of the year, up 7.9 percent from a year ago.

Excluding top-cap Samsung Electronics Co., however, the figure stood at 82 trillion won, down 0.1 percent. (Yonhap)