Advanced Semiconductor Engineering (ASE), which has already purchased 25% shares of Siliconware Precision Industries (SPIL), has announced new plans to acquire another 25% stake in the fellow packaging and testing company.

ASE disclosed plans to buy up to 770 million common shares of SPIL, which will include common shares represented by American depositary shares (ADS), equivalent to 24.71% of the issued and outstanding shares of SPIL. ASE will offer NT$55 (US$1.67) per common share of SPIL and NT$275 per ADS.

The tender offer price represents a premium of about 9.8% over SPIL's closing price of NT$50.10 on the Taiwan Stock Exchange (TSE) on December 21.

ASE in October completed its tender offer for SPIL and obtained a 25% stake in the company. The aim of the stake acquisition is to "establish the basis and opportunity for exploration of possible avenues of cooperation between the two companies," ASE said. "SPIL's management has acted with animosity towards ASE and continuously disregarded ASE's proposals to engage in discussions on potential cooperation, and has taken various actions that are ill-advised from a corporate governance perspective."

SPIL had proposed a share-swap deal with Foxconn Electronics (Hon Hai Precision Industry), which did not get enough support from its shareholders. Most recently, SPIL announced plans to have China's Tsinghua Unigroup subscribe to the company's new shares to become the largest shareholder of SPIL, which will still require regulatory and shareholder approvals.

In addition, SPIL has filed a civil lawsuit in Taiwan against ASE requesting the court confirm that ASE does not have the right to register as a shareholder of the company. "ASE's tender offer violated the Securities and Exchange Act, Fair Trade Act and other related regulations and breaching public order, and thus should be invalid," SPIL said.

"In order to protect ASE's investment in SPIL, ASE plans to launch this tender offer for the purpose of increasing its shareholding in SPIL to approximately 49.71%," ASE noted. "After the completion of this tender offer, ASE reserves the right to increase or decrease its shares in SPIL, exercise its right as a SPIL shareholder, or take one or more actions to enforce and protect its interest in SPIL and/or to enhance its control in SPIL."

ASE previously proposed to acquire all outstanding shares of SPIL for NT$55 each. The 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. ASE believes that the deal between SPIL and Tsinghua Unigroup would significantly dilute the equity interests of SPIL's shareholders. SPIL has responded saying ASE's takeover offer will be discussed at its board meeting on December 28.