Registrants shall retain the records for an application for apportionment registration required by s. Trans 152.11 for 51/2 years. Failure to timely provide records demanded for the purpose of audit extends the statute of limitations for assessment of additional tax by the department until 9 months after the records are provided. Successive failures to adequately respond to a demand for records relate back to the first demand. The record retention period is extended indefinitely by refusal to provide documents.
Wis. Admin. Code Department of Transportation Trans 152.12