Advanced Semiconductor Engineering (ASE) has raised its stake in Siliconware Precision Industries (SPIL) to more than 30% through open market purchases.

ASE on March 28 issued a company filing with the Taiwan Stock Exchange (TSE) disclosing the company had acquired 30,458,004 SPIL shares at a price of NT$53.15 (US$1.63), or a total of about NT$1.62 billion. The acquisition boosted ASE's stake in SPIL to 31.42%, according to the filing.

ASE obtained a 25% stake in SPIL through an unsolicited tender offer successfully executed in October 2015. ASE launched another tender offer in December aiming to grab a controlling stake in the fellow packaging and testing house. The bid, however, failed to obtain regulatory approval before it expired on March 17.