The profitability of South Korea's leading tech and auto companies has worsened this year to lag behind that of their global peers, dragging down their share prices and adding pressure to the overall stock market, data showed Monday. 

The return on equity of major exporters in Asia's fourth-largest economy has slipped over the past years in the face of tougher competition from rising Chinese rivals and global leaders in the high-end market.

ROE, calculated by dividing net income by equity capital, measures a firm's ability to generate returns from invested capital.

Samsung Electronics Co., the world's largest handset maker, saw its ROE stand at 16.4 percent at end-July, according to its regulatory filing, falling far below that of U.S. archrival Apple's 39.2 percent.

The Korean tech giant's ROE was 23.8 percent in June 2013, just behind Apple's 26.3 percent, but it dipped to the 16 percent level this year due to its sluggish mobile business.

The share price of Samsung Electronics broke through 1.5 million won on March 19, but it tumbled to just over 1.1 million won in early August amid a bleak outlook for its high-end smartphones.

The ROE of Hyundai Motor Co., South Korea's top automaker, came in at 10.9 percent at end-July, its financial reports showed, outpaced by Japanese carmaker Toyota's 13.9 percent and German automaker Volkswagen's 11.7 percent.

The situation reversed after Hyundai Motor's ROE marked 21.3 percent in December 2011, while that for Toyota and Volkswagen was at 5.9 percent and 11.1 percent, respectively.

Hyundai Motor's global market share has waned because the Korean automaker's price competitiveness has weakened amid the weaker Japanese yen, while German automakers have aggressively marketed premium brands.

The market heavyweights' lackluster profitability pushed down the main KOSPI market over the past weeks, which has fared worse than the tech-heavy KOSDAQ, amid growing uncertainties in the global economy.

"Not only Samsung Electronics and Hyundai Motor but also other industry leaders saw their profitability decline," said Bae Sung-yung, a researcher at Hyundai Securities. "The local stock market has been on a fragile footing because large caps have been suffering worsening competitiveness." (Yonhap)