Japan Post Insurance Co Ltd, 64%-owned by Japan Post Holdings, first revealed in July last year it had mismanaged insurance policies affecting thousands of clients and said it was suspending such sales.
The case pushed corporate governance to the fore just as the government planned to sell $10 billion worth of shares in Japan Post Holdings to fund reconstruction in areas devastated by an earthquake and tsunami in 2011.
"We have largely lost trust from customers. We have to start over to regain trust so that customers will use our service and products again," Japan Post Holdings Chief Executive Hiroya Masuda said at a news briefing.
Japan's financial regulator in December ordered Japan Post Insurance to stop marketing insurance policies, which were sold at outlets of postal service unit Japan Post, until March. But the company continued to suspend sales while it conducted an internal investigation.
Japan Post Holdings has said it was punishing some 2,400 employees in relation to the case.
(Reporting by Takashi Umekawa; Editing by Chang-Ran Kim and Kim Coghill)