“….appraiser stated divide average of 3 years of Ordinary Business Income + Rent by the cap rate to come up with the appraisal value…..”
This is a technique used in one method of the income approach to value.
Income approach methods include gross income multiplier, capitalization, discount cash flow analysis (estimating reversion values), highest/best use analysis and mortgage equity capitalization.
Generally speaking, capitalization rate would be applied against the 3-year weighted average (not the mean or arithmetic average) available cash flow (NOI) where the most recent results carry greater weight in the 3-year span.
“…..cap rate could be 10% and is based on risk involved with management, and business in general. Is this some arbitrary number that they just make up?”
No, but it is somewhat subjective.
For example, cap rates are affected by increases in supply and demand and interest rates.
So, if my anticipation of these factors is different from another person’s, our opinions of value may be different.
Higher cap rates (lower property values) tend to be brought about if owner is unable to remain to transition the business, if facilities require significant capital investment, and other conditions.
Lower cap rates (higher property values) tend to be brought about if there are significant barriers to entry, history of increasing earnings, attractive environment, etc.