Jason Chang, chairman for Advanced Semiconductor Engineering (ASE), spent a total of about NT$1.3 billion (US$40.9 million) of his own money to buy ASE shares from August 17 to 26.

ASE has responded saying the stake purchase should be considered as purely the behavior of an individual investor.

ASE's SEC filings disclosed that Chang used his own money to acquire 34.3 million ASE shares in the open market during the 10-day period. Chang is already the largest shareholder of ASE.

ASE added Chang is optimistic about ASE's operations in the future and therefore intended to raise its holding in the company.

ASE has entered into a merger agreement with Siliconware Precision Industries (SPIL), under which a new company will be established to own both ASE and SPIL. ASE and SPIL will become parallel sibling companies under the new entity, which will trade its shares on the Taiwan Stock Exchange and the New York Stock Exchange, while shares of ASE and SPIL will all be delisted. The pair has submitted applications with anti-trust authorities in China, Taiwan, the US and others seeking approval for their proposed merger slated for completion by the fourth quarter of 2017.

The proposed merger of ASE and SPIL will create the world's largest IC backend house with a nearly 30% market share, widening the market gap against rival companies including Amkor Technology, and China-based Jiangsu Changjiang Electronics Technology (JCET), according to Digitimes Research.