In July 2017, the Financial Services Agency published a report on rotating audit firms. It looked at 96 of the TOPIX 100 companies that had also been in the index in 2007. Over the ten years to 2016, 91 of them, 95 percent, had kept the same audit firm. Five had changed.
Agency materials of 2022 described the same pattern: audit contracts had become fixed, and companies were not changing audit firms of their own accord.
In the first half of 2026, Tokyo Shoko Research counted 91 changes of auditor. The most common reason given, in 42 cases, was the length of the audit tenure itself.