Advanced Semiconductor Engineering (ASE), Siliconware Precision Industries (SPIL), Powertech Technology (PTI) and Sigurd Microelectronics, four Taiwan-based providers of IC packaging and testing services, saw their unaudited consolidated revenues for December 2011 decrease on month and year.

ASE and SPIL are expected to suffer 5-10% sequential decreases in consolidated revenues for the first quarter of 2012, while PTI will see a 10-15% drop, according to market analysts.