The WSTS is an alliance of the world's main chip makers, representing 85 percent of global sales.
But global chip sales fell in December compared with November as last year's expansion slowed in the fourth quarter due to inventories and pricing pressure.
December sales totalled $18.37 billion, 3.5 percent lower than in November, but still up 14.6 percent compared with the same month a year earlier. Looking at year-on-year comparisons, December growth was well below the 28 percent increase for the year as a whole.