Hoya Corp. said Friday it would make a $1.4 billion counterbid for NuFlare Technology Inc. in what could become a hostile offer for the Toshiba Corp. unit the electronics conglomerate plans to buy out.

Hoya's interest in the manufacturer of chipmaking equipment further complicates a deal already being driven by activist investor Yoshiaki Murakami, which has amassed a 6.2 percent stake.

With Hoya offering a sweeter deal, it could also become another test case for Japan's corporate governance when it comes to seeking higher returns for shareholders. Hoya is offering ¥12,900 — ¥1,000 more than Toshiba — valuing NuFlare at ¥147.7 billion ($1.4 billion).