SEOUL, Jan. 8 (Xinhua) -- Samsung Electronics, the world's biggest maker of memory chips, display panels and TVs, posted a double-digit fall in operating profit in the fourth quarter of last year, a regulatory filing showed Tuesday.

Preliminary figure for operating profit was 10.8 trillion won (9.6 billion U.S. dollars) in the October-December quarter, down 28.7 percent from a year earlier.

It was down 38.5 percent from the prior quarter when the South Korean company logged its record-high operating profit. The figure missed market expectations of about 13.4 trillion won (11.9 billion U.S. dollars).

Revenue declined 10.6 percent over the year to 59 trillion won (52.5 billion U.S. dollars) in the December quarter.

Net income and earnings of each business would be announced later this month after external audit and approval by board of directors.

Samsung said its memory chip-making business saw a sharp decline in earnings on weak global demand amid the expanded external uncertainties, noting that the earnings of its smartphone division went down in the fourth quarter on stiffer competition with rival manufacturers.

The company forecast that the slump in its memory chip business would continue in the first quarter on soft global demand before recovering in the second half of this year.

Demand was estimated to have weakened in the fourth quarter for Samsung products, ranging from chips to mobile phones, amid the global economic slowdown caused mainly by trade conflict among major economies.

The iPhone maker, Apple, is one of Samsung's biggest customers for memory chip and display panel. Apple sharply lowered its earnings guidance for the fourth quarter.

Market watchers said Samsung's earnings in consumer electronics business outperformed in the fourth quarter on demand for premium TVs, estimating the reduced earnings in smartphone and memory chip businesses.

The smartphone unit's operating profit was estimated at about 1.6 trillion won (1.4 billion U.S. dollars) for the fourth quarter, after recording 2.2 trillion won (2 billion U.S. dollars) in the previous quarter.

The chip-making division's operating profit was estimated at less than 10 trillion won (8.9 billion U.S. dollars) in the fourth quarter, down from 13.7 trillion won (12.2 billion U.S. dollars) in the prior quarter.

For the entire year of 2018, Samsung's revenue reached a new high of 243.5 trillion won (216.6 billion U.S. dollars), up 1.6 percent from the previous year.

Operating profit grew 9.8 percent over the year to hit a new record high of 58.9 trillion won (52.4 billion U.S. dollars) in 2018.

However, more than three-fourths of Samsung's 2018 operating profit stemmed from the chip-making unit, of which operating profit was estimated at about 45 trillion won (40 billion U.S. dollars).

Samsung's earnings this year are expected to slump in the first half on lower memory chip price.