Sony CEO Howard Stringer faced criticism of his leadership after the consumer electronics giant revealed hackers may have stolen the data of another 25 million accounts in a second massive security breach.
Sony's latest revelation came just a day after it announced measures had been put in place to avert another cyberattack like that which hit its PlayStation Network, hoping to repair its tarnished image and reassure customers who might be pondering a shift to Microsoft's Xbox.
The Japanese electronics company said its Sony Online Entertainment PC games network had been hacked on April 18, but did not find out about the breach until the early hours of Monday and shut down the service shortly afterwards.
The breach may also have led to the theft of 10,700 direct debit records from customers in Austria, Germany, the Netherlands and Spain and 12,700 non-US credit or debit card numbers, it said.
Investors said Sony and 69-year-old chief executive Stringer had botched the data security crisis, a further blow for the company which has struggled against rivals including Nintendo and lost ground to smartphone makers such as Apple Inc
"The way Sony handled the whole thing goes to show that it lacks the ability to manage crises," said Michael On, fund manager at Beyond Asset Management in Taipei.
"The current CEO should step down after the hacker problems and the company's failure to push out products that are competitive."
Stringer has not commented on the security breach, leaving number 2 Kazuo Hirai to lead the news conference and apology on Sunday.