South Korean tech giant Samsung Electronics Co. estimated Tuesday that its second-quarter operating profit fell 4.03 pct on-year as weak sales of the Galaxy S6 smartphone lineup overshadowed improved returns from its chip segment.

Operating profit for the April-June period reached 6.9 trillion won (US$6.13 billion), compared with the 7.19 trillion won posted a year earlier, the world's top smartphone maker said in a preliminary earnings forecast.

The estimate, however, marks a 15.38 percent rise from the operating profit of 5.98 trillion won posted during the January-March period of 2015.

The figure was out of line with the median forecast of 7.1 trillion won by 18 local brokerage houses polled by Yonhap Infomax, the financial news arm of Yonhap News Agency.

Samsung's second-quarter sales came to 48 trillion won, down 8.31 percent from 52.35 trillion won a year earlier. The market consensus stood at 52.1 trillion won.

Samsung didn't offer a net profit estimate for the second quarter.

Shares of Samsung Electronics closed at 1,230,000 won Monday on the main bourse, plunging 3 percent from the previous session, while the KOSPI surrendered 2.4 percent. The guidance was released before the local stock market opened. (Yonhap)