GMO Internet stock plunges 13.6% after forex cloud cyberattack

GMO Internet Group's stock plunged 13.6% to 3,256 JPY on Monday following a severe cyberattack on its leveraged forex trading cloud service, prompting investors to flee the stock. The breach involved unauthorized access to customer server environments and fraudulent trades in accounts, culminating in a ransom demand on October 24 and a public apology from CEO Masatoshi Kumagai on October 25, who admitted internal engineers had previously identified unaddressed security flaws. The company will compensate all affected customers with a 5,000 JPY goodwill payment and cover trading losses from unauthorized transactions, an open-ended commitment the market struggles to quantify. It also filed a formal request with the Japanese government to strengthen proactive national cyber defenses, while the broader TOPIX index fell 0.8%.