SEOUL - Samsung Electronics and Hyundai Motor accounted for more than half of net profits generated by top 100 companies by sales in South Korea, boosting concerns over excessive dependence on a few number of companies, local media reported Wednesday.

Top 100 South Korean companies listed on the main bourse posted a combined 48.73 trillion won ($43 billion) in net profits in 2012, according to data by the Korea Exchange cited by the local daily ChosunIlbo.

Samsung Electronics, Hyundai Motor and its affiliate Kia Motors logged a total of 24.8 trillion won in net income last year, accounting for 51 percent of the total.

The share of net profits generated by the big three companies continued to increase from 19 percent in 2007 to 35 percent in 2009, 36 percent 2011 and the record high of 51 percent 2012, according to the report.

The heavy dependence on a few number of companies boosted concerns over the South Korean economy, which saw its gross domestic product (GDP) expand less than 1 percent for the past eight straight quarters.

Samsung kept its record-breaking earnings trend over the past years, but it depended on smartphone for around 70 percent of its total sales. The end of smartphone boom could lead the company into trouble with generating record-breaking profits.

Hyundai saw its operating profit for the first quarter decline 10.7 percent from a year earlier amid worries about the weak yen trend that was feared to hurt the company's price competitiveness compared with Japanese rivals.

The yen/dollar exchange rate rose fast since September last year, topping the 100 yen level in around four years earlier this month. More than 20 percent depreciation of the Japanese yen versus the dollar over the cited period was faster than any other descending period.