Siliconware Precision Industries (SPIL) has confirmed on December 14 that the company received a proposal submitted by Advanced Semiconductor Engineering (ASE) to acquire all outstanding SPIL shares in cash.

SPIL indicated it will discuss ASE's proposal at an upcoming board meeting scheduled for December 28.

ASE said previously it would spend about US$4 billion to acquire SPIL's remaining stake for NT$55 (US$1.67) per share. ASE currently holds a 25% stake in SPIL.

ASE's unsolicited offer came on the heels of SPIL's announcement that the company plans to sell 1.03 billion new shares to Tsinghua Unigroup at NT$55 – the same price that ASE has offered.