More companies in Japan have reported data breaches as public scrutiny grows over security measures taken by businesses.

Tokyo-based information technology services firm Paycloud Holdings said Monday that about 77 million email addresses were leaked after hackers gained unauthorized access to servers operated by its subsidiary, which runs the email distribution service Arara Message.

The breach exposed the registered information held by up to about 380 corporate clients using the service. Depending on the company, the leaked data also included names, telephone numbers and addresses, Paycloud said. No credit card numbers were leaked.