Shares in Japanese game developer Sega Sammy Holdings Inc fell on Monday after news leaked that hackers breached the company's networks and stole information from 1.3 million customers.
Shares of Sega were down 1.8 percent to 1,581 yen after sinking as much as 5 percent at one point.
Sega issued a warning saying that it had been infiltrated by cyber criminals and personal information on over 1 million customers was compromised.
The company said on Friday that its SEGA Pass service, operated by Sega Europe, came under attack and a number of user accounts were illegally accessed.
The service was illegally accessed from outside and personal information of all 1,290,755 customers of the service... were brought outside of the system, according to SEGA. The information included names, birth dates, e-mail addresses and encoded passwords, the statement said.
In a span of just a few weeks, several multinational companies and even government agencies have fallen victim to cyber crime.
Joining those ranks, Sega said that it has launch an investigation and took steps to secure data.
Over the last 24 hours we have identified that unauthorized entry was gained to our Sega Pass database, the company said.
We immediately took the appropriate action to protect our consumers' data and isolate the location of the breach. We have launched an investigation into the extent of the breach of our public systems.
Passwords were encrypted and no financial data was accessed, it said.
Several other companies have fallen victim lately as well.
On Wednesday the public website of the CIA went down, with the hacker group Lulz Security saying it had launched the attack.
Although the group fashions itself more as pranksters and activists than people with sinister intent, its members have been accused of breaking the law and are wanted by the FBI and other law enforcement agencies.
Lulz broke into a Senate website over the weekend and released data stolen from the legislative body's computer servers.
In May, the group posted a fake story on the PBS website saying that rapper Tupac Shakur was still alive and living in New Zealand.
The group denied any involvement in the Sega case, however, asking Sega to instead contact them to help destroy the hackers that attacked you.
But it does underline mark an uptick in crime over the Internet
The last high-profile victim was the International Monetary Fund this weekend, who's computer network was breached by what was believed to be a government backed effort.
Just last week banking giant Citibank confirmed that credit card data of about 200,000 of its North American customers have been hacked. The event marked the largest attack on a bank in the US to date.
The week before US military contractor Lockheed Martin was compromised as hackers used Lockheed's own secure id technology to access its networks.
Google has accused Chinese hackers of targeting the Gmail accounts of U.S. government officials.