What must an appraiser do if they employ an extraordinary assumption in an appraisal?

When an appraiser employs an extraordinary assumption in an appraisal, it is essential to state that this assumption could affect the results of the appraisal. An extraordinary assumption is a specific assumption that, if found to be false, could alter the appraiser’s opinion of value. By clearly stating that this assumption is in play and acknowledging its potential impact on the final value estimate, the appraiser takes a responsible approach to transparency and provides the client with a clear understanding of the risks involved. This helps to ensure that all parties are aware of the conditions under which the appraisal is being performed and the potential implications on the outcome.

While it might seem beneficial to include full reports of assumptions or submit additional documentation, these actions are not explicitly required concerning extraordinary assumptions. The primary obligation is to make clear the nature of these assumptions and their potential effect on the appraisal's conclusions. Marking the appraisal as provisional is also not a standard requirement for handling extraordinary assumptions.