Advanced Semiconductor Engineering (ASE) is expected to see its 2015 profits hit the second-highest level in the company's history, while fellow packaging and testing company Siliconware Precision Industries' (SPIL) profits will stay high at 2014 levels, according to industry sources.

ASE's gross margin for the fourth quarter of 2015 is likely to stay flat on quarter, said the sources. Meanwhile, the company's SiP (system-in-package) business is expected to account for 25-30% of its overall revenues in the fourth quarter.

SPIL, which saw its net profits surge 99% on year to NT$11.73 billion in 2014, is set to report flat profit growth for 2015, the sources indicated.

ASE has reported consolidated revenues increased 3.7% sequentially to NT$75.6 billion (US$2.2 billion) for the fourth quarter of 2015. The result was the second-highest quarterly level in the company's history. Revenues came to NT$283.3 billion in 2015, rising 10.4% on year.

SPIL posted revenues of NT$20.77 billion in the fourth quarter of 2015, up 3.7% on quarter. Revenues for all of 2015 slid 0.3% to NT$82.84 billion.

ASE and SPIL will hold investors meetings on January 29 to detail their 2015 operations and guidance for the first quarter of 2016.