The top executive of Japan Post Holdings Co. said Wednesday he is considering resigning in the wake of a probe that uncovered more than 12,000 cases of suspected improper sales of insurance products at two subsidiaries in the five years through March 2019.

"Regarding management responsibility, I will announce it at an appropriate time," said Masatsugu Nagato, the chief executive of the former state-owned postal and financial services group, at a news conference in Tokyo. "There is a broad range of stakeholders, and each has a different responsibility, so the management will need to discuss the matter thoroughly."

A company panel probed 183,000 suspected cases of improper sales at Japan Post Insurance Co. and Japan Post Co. The report found that of those, violations of a law or in-house rules are suspected in 12,836 cases.