The new federal partnership income tax audit rules, scheduled to take effect on January 1, 2018, will have significant implications for the state and local taxation of partnerships and their partners. Most, but not all, states that impose a net income-based tax adopt by reference the federal definition of taxable income, but those that do typically adjust that income to reflect differences between state and federal tax policies. Moreover, state revenue departments generally do not regard themselves as being bound by Internal Revenue Service interpretations of the Internal Revenue Code even when substantive Code provisions are incorporated into state law by reference. The federal statutory rules relating to partnership audits are procedural rules and not ones of substantive tax law, so they will not be automatically adopted by states that generally conform to Internal Revenue Code provisions relating to taxable income. State legislatures may decide to adopt some or all of the federal statutory rules, or they may decide to adopt none of them. Arizona has already adopted its own version of the federal rules, and other state revenue departments are considering recommending to their legislatures that the legislatures take similar action, but most states have not reacted to the federal rules at this time. (more…)