SEOUL, April 6 (Xinhua) -- Samsung Electronics posted an earnings surprise in the second quarter on brisk sales of semiconductor and smartphone, the company said Friday.

Preliminary figure for operating profit was 15.6 trillion won (14.7 billion U.S. dollars) in the January-March quarter, topping the previous quarterly high of 15.15 trillion won (14.2 billion U.S. dollars) tallied in the fourth quarter of last year.

It was up 57.6 percent from a year earlier, beating market expectations of about 14.5 trillion won (13.6 billion U.S. dollars).

Revenue advanced 18.7 percent over the year to 60 trillion won (56.4 billion U.S. dollars) in the quarter, surpassing 60 trillion won for the fourth consecutive quarter.

Net income and more details on profits of each business unit would be announced later this month after an external audit and the board of directors' approval.

The ratio of operating profit to revenue jumped 6.4 percentage points to 26 percent in the first quarter. It was the highest in the company's history.

The record-breaking earnings came as the global memory chip market kept booming. Market watchers estimated that almost three-quarters of Samsung's first-quarter operating profit was generated in the chip business.

The smartphone unit was also believed to have made better-than-expected profit thanks to the early release of the flagship smartphone Galaxy S9 and the continued sales of previous models.

Samsung's display panel division was estimated to post a big fall in operating profit in the first quarter due to weak sales of Apple's iPhoneX. Samsung is one of Apple's main flat screen suppliers.

The consumer electronics unit was also believed to see a weak profit in the quarter compared with its semiconductor and smartphone businesses.

The trend of Samsung's solid earnings was forecast to continue in the second quarter on the expected strong sales of memory chips, recovered display panel shipments and the reduced costs in the smartphone business.

Market watchers expected Samsung to post 62.4 trillion won (58.6 billion U.S. dollars) of operating profit on revenue of 260.8 trillion won (245.1 billion U.S. dollars) in the entire year of 2018.

In 2017, the company logged its record yearly earnings with 53.65 trillion won (50.42 billion U.S. dollars) in operating profit and 239.56 trillion won (225.13 billion U.S. dollars) in revenue.

Despite the rosy outlook, negative risk factors facing Samsung remained such as the U.S. protectionist moves that were expected to hit hard Samsung's chip and smartphone businesses.

The U.S. protectionist moves were feared to shrink the global trade and negatively influence the overall exporters of South Korea, which depends on exports for about half of the gross domestic product (GDP).

The South Korean currency continued to rise versus the greenback, reducing the repatriated revenue of Samsung's overseas sales. Samsung's first-quarter revenue missed market expectations on the strong local currency.