LG Display, the world's second- largest LCD maker, reported fourth-quarter profit beating market estimates due to strong demand from Apple.

Operating profit was 587.3 billion won (550 million U.S. dollars) in the three months ended Dec. 31, after posting a 154.7 billion won loss a year earlier, the company said in a regulatory filing on Thursday. The profit almost doubled from three months before.

Revenue increased 32.3 percent to 8.7 trillion won, and net income swung into black worth 319.7 billion won after recording a 6.3 billion won loss a year ago. "We expect LG Display's 4Q results to come in line with our forecasts for an operating profit of 434 billion won," Jonathan Hwang, an analyst at Daewoo Securities in Seoul, said in a report before the release. Panel shipments "surged in 4Q thanks to the launch of new devices like the iPhone 5, iPad mini, Mac computers and Apple Macbooks."

Shipments of screens for iPhone 5 and iPad mini reached 21 million units and 8 million units each during the quarter, according to an estimate by Korea Investment & Securities analyst Yoo Jong Woo. Apple accounted for around 20 percent the LG Electronics affiliate's sales last year, Yoo said, noting that the reading rose to 27 percent in the fourth quarter from 16 percent in the first half.

Outlook for the first-quarter earnings was gloomy as shipments of panels for 9.7-inch iPads fell after the launch of low-margin 7. 9-inch iPad mini in October. Shipments of screens for the iPads plunged to 1.5 million units in November from more than 4 million units in October, according to Daewoo Securities.

Shares in LG Display declined 1.2 percent to close at 28,550 won before the earnings announcement. The main KOSPI index fell 0. 8 percent. Endi