SEOUL, Jan 24 (Reuters) - Samsung Electronics Co Ltd posted its first decline in quarterly profit in two years, hit by a one-off special bonus as well as slowing smartphone sales as it braces for a year of tougher competition with rival Apple Inc.
The South Korean maker of Galaxy-brand smartphones said October-December operating profit fell 6 percent on year to 8.3 trillion won ($7.73 billion), in line with its previous estimate.
Operating profit at its cash cow mobile division stood unchanged at 5.47 trillion won, but slipped 18 percent from July-September's record 6.7 trillion won as new iPhones from Apple drew away sales during the year-end holiday period.
Shares of Samsung Electronics, worth $204 billion, closed down 2.2 percent on Thursday, compared with the benchmark index which was 1.2 percent lower. ($1 = 1073.9500 Korean won) (Reporting by Miyoung Kim; Editing by Christopher Cushing)