TOKYO (Reuters) – Japan’s Hoya Corp said on Friday it would make a $1.4 billion counter-bid for NuFlare Technology Inc in what could become a hostile offer for the Toshiba Corp unit, which the electronics conglomerate plans to buy out.

Hoya’s interest in the manufacturer of chip-making equipment further complicates a deal already being challenged by Japanese activist investor Yoshiaki Murakami, which has amassed a 6.2% 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 yen – or 1,000 yen more than Toshiba – valuing NuFlare at 147.7 billion yen ($1.4 billion).

NuFlare was not immediately available for comment.

Toshiba, which owns 52.4% of NuFlare, said last month it would launch a tender offer to buy the rest of the firm as part of efforts to overhaul its vast asset portfolio.

Hoya said it wants to buy at least two-thirds of NuFlare, meaning it would need Toshiba to sell at least part of its stake for the deal to go through. Hoya said the price was competitive enough to entice Toshiba to tender its shares.

But Toshiba said in a statement there was no change to its plan to make NuFlare a 100% unit, which it said was “the best option for maximising NuFlare’s corporate value”. Its offer price of 11,900 yen had been agreed upon with a special committee set up by NuFlare and was “appropriate”, it said.

“While U.S. and European firms consider various options for restructuring, Japanese companies tend to fix upon only one. Once Toshiba decided to buy NuFlare, it doesn’t seem to have an alternative,” said a Tokyo-based investment banker.

Hoya would abandon its plans if it fails to take a minimum 66.67%, it said.

Shares in NuFlare jumped 11.7% to 13,330 yen in Tokyo.

Toshiba’s plans to acquire NuFlare come as Japanese companies are under pressure to resolve conflicts of interest between publicly traded parent companies and their listed subsidiaries.

Toshiba has said plans to spend 200 billion yen to convert NuFlare, plant engineering firm Toshiba Plant Systems & Services and marine electrical systems maker Nishishiba Electric Co into wholly owned units.