How the Assessor Estimates Your Market Value: Minnesota Property Tax

This fact sheet is the second in a series of three fact sheets that were designed to assist taxpayers in the understanding of the basic concepts of their annual assessment and property tax administration. Please see Fact Sheets 12a and 12c for additional information.

Property Tax Assessment Process

Minnesota has what is known as an ad valorem property tax. This means property tax is divided among taxable properties according to their value. The final amount of property tax the owner of a property pays in any given year is the end result of a process that begins over two years before property tax statements are actually mailed to property owners.

The process begins with the assessor collecting data on sales of properties within the market during a specific time period between October of one year and September of the following year (this period is known as a sales study period). Over the next several months and by using mass appraisal techniques, assessors analyze the data in order to estimate each property’s market value for the next assessment (January 2). Pursuant to Minnesota Statutes, section 273.11 assessors must estimate the value of property at a value that would represent what the property would sell for in an open-market arm’s length transaction on January 2 of each year. The assessor cannot adopt a higher or lower standard of value because the value will be used for the purposes of taxation.

Assessors also classify property according to its use on January 2. Between April and June, taxpayers have an opportunity to appeal both the estimated market value and the classification of their property. Values and classifications are generally finalized July 1 of each year.

Local units of government then finalize their estimated budgets for the upcoming year. Once the budgets are finalized in December, the market values and classifications are used to divide the overall tax levy among all taxable properties. Tax statements are mailed by the following March 31.

For example, sales of properties that occur between October 1, 2008 and September 30, 2009 are used by assessors to estimate a property’s market value for the January 2, 2010 assessment. Following an appeal process that occurs between April 1, 2010 and June 30, 2010, the valuations and classifications generally become final on July 1, 2010.

This lengthy time frame may result in a significant difference between actual sales prices occurring in the current market and assessors’ estimated market values for the current year’s assessment.

Using the final values and the local jurisdictions’ proposed budgets, the auditor then estimates each property’s proposed taxes payable for 2011. After public budget meetings are held and final budget numbers are adopted, property tax statements are mailed to taxpayers by March 31, 2011.

In summary, sales taking place from October 2008 to September 2009 are used to estimate a property’s market value as of January 2, 2010 which will in turn be used to calculate property taxes payable in 2011.

What is the role of the assessor?

Assessors use historical sales in order to estimate each property’s market value as of the assessment date (January 2) of each year. The assessor also classifies the property according to its use on January 2 of each year.

Assessors also review other quantifiable data such as supply/demand, marketing times, sales concessions, vacancy rates, etc. to help in analyzing whether a market is increasing, stable, or decreasing.

During increasing markets, this may benefit some property owners because a buyer may pay a price that is significantly higher than the assessor placed on the property for the last assessment. For example, if a property is valued by the assessor at $180,000 for the 2009 assessment (based on sales that occurred between October 2007 and September 2008), and it sells for $230,000 in August 2009, the new property owner is benefiting from the lower market value for the 2009 assessment which will be used to calculate taxes payable in 2010.

The August 2009 sale of the property will be included in the study period of October 2008 to September 2009 which the assessor will use to value property for the 2010 assessment for taxes payable in 2011.

This same lag time is also present in declining markets. For example, if the assessor places a market value of $200,000 on a property for the 2009 assessment (again using sales that occurred between October 2007 and September 2008), but the property sells for $175,000 in August 2009, does it mean the January 2, 2009 assessed value is incorrect? Not necessarily. It could signal a downturn in the housing market just began to occur between September 2008 and August 2009. The assessor will use the August 2009 sale as well as others occurring in the market to estimate 2010 market values.

The assessor does not raise property tax revenues by increasing values. Total property tax revenues are a function of county, school district, and city/town spending as well as state-paid local government aid and other factors. The value and classification of the property are merely a way to divide the total property tax levy among all taxpayers. The total amount of the levy will be collected whether values increase or decrease from one year to the next. An individual’s share of the overall tax burden may change from year to year, however.

What are sales ratio studies?

Sales ratios show the relationship between the assessor’s estimated market value on a property and the actual sale price of a property.

Each year the assessor performs sales ratio studies on properties that have sold in their jurisdiction. These sales are stratified many different ways including by location and property type (residential, agricultural, commercial, etc.). The sales can also be stratified further such as by home style, subdivision, age of structure, location on or off water frontage, price range, etc.

A single sale may not represent the true market activity. Rather, sales of all properties are reviewed to determine market trends. However, even if there are no sales occurring within the sales ratio study period, assessors are still expected to use their professional judgment and knowledge of the local market to annually value properties in their jurisdiction.

Whenever any real estate is sold for a consideration in excess of $1,000, a Certificate of Real Estate Value (CRV) is filed. These CRVs are the foundation of all sales ratio studies because they contain important information about each transaction. Assessors then verify the information contained on the CRV in order to determine whether or not the sale represents an open-market arm’s length transaction. If the sale does not represent an open-market, arm’s length transaction, it may not be used in the sales ratio study.

Simply having an extremely high or low sales ratio is not a valid reason to remove a sale from the sales ratio study. Rather, the extreme ratio indicates a need for additional investigation by the assessor.

Again, sales ratio study periods are generally October 1 of a given year to September 30 of the following year. For example, for the 2010 assessment, assessors use sales that took place between October 1, 2008 and September 30, 2009. This is the reason that assessors’ market values may lag a bit behind current market activity.

Assessors will use the median sales ratio as the statistical measure of the overall level of assessment. The median ratio is the middle ratio of all the ratios when they are arranged in order from highest to lowest (or vice versa). The median is used because it is not affected by extreme ratios. Department of Revenue guidelines indicate that the median ratio of a sales ratio study should be between 90 and 105 percent.

Is it possible for the values of some properties to decrease while others increase?

Yes. Each segment of the market is different. Sales prices of certain types of properties can vary widely. Currently, sales of both farmland and recreational properties are strong and show appreciation. However, the sales of residential properties are stable or declining in some areas.

Sometimes it can be difficult to estimate the rate at which a market is increasing or declining. Ideally, a property would sell twice within a certain period of time, such as one year, but all other characteristics of the property would remain the same. That way an appraiser or assessor would be able to isolate a time adjustment to indicate whether the market is increasing or decreasing or simply remaining stable.

Do all areas increase or decline at the same rate?

No. Some areas or neighborhoods are declining at a much faster rate than others that are showing stable values or values that are slightly increasing.


In conclusion, it is essential that taxpayers understand that there may be a legitimate reason for the assessor’s annual market value to be different from current market conditions due to the lag time between sales study periods and sales taking place today.

For additional information, please refer to Fact Sheet 12a Understanding Property Taxes and Fact Sheet 12c Understanding Your Assessment and the Appeals Process.

This fact sheet is intended to help you become more familiar with Minnesota tax laws and your rights and responsibilities under the laws. Nothing in this fact sheet supersedes, alters, or otherwise changes any provisions of the tax law, administrative rules, court decisions, or revenue notices. Alternative formats available upon request.

The content of this and any related posts has been copied or adopted from the Minnesota Department of Revenue Property Tax Fact Sheet 12b.