Samsung Electronics predicted on Friday that its quarterly operating profit has hit a fresh high, spurred by robust smartphone sales and the selloff of its hard-disk drive unit.

Operating profit shot up a staggering 72.8 percent on-year to 5.2 trillion won ($4.5 billion) between October and December 2011, the world’s largest maker of handsets and memory chips said in a regulatory filing. 

The preliminary results beat the average market projection of 4.81 trillion won. Analysts estimate 16.2 trillion won for the whole of 2011.

Quarterly sales are expected to reach a record 47 trillion won, up about 12.3 percent from a year ago.

Samsung did not provide net income figures or details on divisional revenue. It plans to release official fourth-quarter earnings later this month.

Shares in Samsung Electronics closed down 1.42 percent, or 15,000 won, at 1.04 million won on Friday after briefly surging in the morning. The price went up nearly 28 percent during the three-month period.

Brisk sales of its Galaxy smartphones were a major impetus for the Samsung’s performance, which fiercely competes with Apple Inc., makers of the popular iPhone. The Korean firm sold more than 300 million units of mobile phones worldwide last year.

In October, Samsung overtook Apple as the world’s largest smartphone vendor, according to Strategy Analytics, a research firm. The two tech giants have been engaged in a patent battle since last year with about 30 lawsuits in 10 countries as they scramble for the top spot in the global smartphone and tablet market.

“Despite soaring marketing costs and some telecom operators’ year-end inventory reduction efforts, Samsung has expanded profit margins by shipping more smartphones,” said Park Young-joo, an analyst at Woori Investment & Securities Co.

Smartphones took up 36.2 percent of total handset sales in the fourth quarter, or 38 million units, according to his calculations. That is up 5.5 percentage points from the same period of 2010.

Sales of displays panels surged also on the back of vigorous demand for mobile phones and high-end televisions in North America, Park added.

In a one-time gain, the company is believed to have raked in up to 700 billion won from the recent sale of its hard-disk drive business to U.S.-based Seagate Technology PLC.

Analysts painted a rosy outlook for Samsung this year as memory chip prices are set to rebound in the first quarter and the smartphone will likely remain the bellwether for the global consumer electronics industry for the time being.

“Samsung Electronics is one of the most promising companies (in Korea) across sectors,” Kim Ji-sung, research head of Nomura Securities’ Korean unit, told reporters on Friday, citing ameliorating prospects for higher earnings this year.

“Samsung shares may rise as much as 20 percent, or even higher if expectations realize that Samsung will instigate changes that could dominate the hardware market.”

By Shin Hyon-hee (heeshin@heraldcorp.com)