MI HB5990

Requires audits performed by the Michigan Department of Treasury to comply with generally accepted government auditing standards published by the U.S. Government Accountability Office and American Institute of Certified Public Accountants' audit sampling guidance.

Mandates that taxpayers audited by the department receive a complete copy of audit work papers, findings, and all supporting correspondence and documentation in printed or electronic format.

Establishes a letter of inquiry procedure requiring the department to notify taxpayers in a courteous manner before assessment, except when taxpayers file returns showing tax due but fail to pay, when deficiency results from a state audit, or when taxpayers admit tax is owed.

Provides taxpayers with a right to an informal conference within 60 days of receiving a notice of intent to assess, allowing them to contest the assessment and present testimony with representation.

Imposes a penalty of $25 or 25% of the contested tax amount (whichever is greater) for frivolous protests or attempts to delay tax administration.