The problem of inappropriate sales practices at Japan Post Insurance Co. — the biggest scandal to hit the Japan Post group since its creation through the 2007 privatization of the nation's postal services — keeps expanding and has severely tarnished customers' trust in the group. Suspicions have also been raised that the group's management may have been aware of the problem when it sold off Japan Post Insurance shares to investors in April. The price of the shares have plummeted following the revelation of the problem in June.

The group admitted late last month that it has mismanaged at least 183,000 insurance policies over the past five years in ways that hurt the customers' interests — such as the customers ending up paying the premiums doubly for new and old insurance contracts or the customers rendered uninsured for several months as they were told to wait before signing a new contract after terminating an old one.

The number is nearly double the 93,000 acknowledged by the group in early July. Some cases involved the outright violation of relevant laws, such as Japan Post salespersons forging contract documents without the customers' consent. The figure may rise even further since the group intends to examine all of Japan Post Insurance's roughly 30 million insurance policies to see if the contracts have been concluded as wished by the customers.