More than a third of South Korea's listed companies experienced earnings surprises in the first quarter on the back of improved results among large firms, data showed Sunday.

A total of 31 out of 100 listed firms that filed earnings reports for the January-March period as of April 30 posted better-than-expected operating profits, according to the data compiled by market tracker FN Guide based on an assessment of 100 listed firms on the benchmark KOSPI and tech-laden KOSDAQ markets.

Brokerages generally classify earnings exceeding market consensus by more than 10 percent as an earnings surprise, while the inverse is referred to as an earnings shock.

The overall improvement in local businesses were largely led by better results seen in large companies, market watchers said.

"Industry leaders, including Samsung Electronics Co. and SK Innovation Co., showed good results, and the shipbuilding and construction sectors are also pulling out of their slumps," said Bae Sung-young, an analyst at Hyundai Securities Co.

Tech giant Samsung Electronics reported an operating profit of 5.98 trillion won ($5.57 billion), 9.9 percent higher than the forecast 5.44 trillion won.

Top oil refiner SK Innovation, whose operating profit swung to the black on-quarter, listed its quarterly earnings at 321.2 billion won, up 45 percent from the 221.5 billion won estimated by investors and securities firms. 

In contrast, the number of companies that suffered an earnings shock came to 38, and while it is higher than the number of earnings surprises, market watchers said overall results were better than they were in the previous quarter.

"There were a lot more firms hit by an earnings shock in the previous quarter, but for the first quarter this year, earnings outpaced expectations in general," Bae said. (Yonhap)