IBM Japan Ltd. said Thursday its group net profit fell 16.6 percent in the business year to Dec. 31 to 79.28 billion yen for the fourth straight annual decline.

IBM Japan traced the slide to restructuring-related extraordinary losses connected to one of its domestic plants.

Group sales fell 5.4 percent to 1.5 trillion yen for the second consecutive year of decline. The fall was attributed to the sale of some of the firm's information equipment operations to Kyocera Corp. in September.

IBM Japan is the Japanese unit of IBM Corp. of the United States.