How the Sales Comparison Approach Works
The sales comparison approach forms the backbone of most residential appraisals. Your appraiser looks at recent sales of similar properties in your neighborhood to estimate what your home is worth. This isn't just a quick scan of recent closings — it's a detailed analysis that considers closed sales, homes currently under contract, and active listings.
Say you're buying a 3-bedroom ranch in a suburban neighborhood. Your appraiser will search for other 3-bedroom ranches that sold recently in the same area, plus any that are currently pending sale or listed for sale. They analyze all three categories because each tells a different part of the market story.
The appraiser must consider every factor that affects value. In a rapidly changing market, this becomes critical. If home prices have been climbing 10% annually, a sale from six months ago might not reflect current value without adjustments. Similarly, if the market has been declining, recent contract sales and listings might show where values are heading.
Required Documentation and Data Sources
Your appraiser must document exactly where they found information about each comparable sale. Vague references like "public records" don't meet Fannie Mae standards. Instead, they need to specify "county tax records," "MLS listing data," or "deed records from the county clerk's office."
Acceptable data sources include multiple listing services, deed records, tax records, real estate agents, builders, other appraisers, and third-party data vendors. The key requirement is that these sources must be reliable for your specific area.
For verification, appraisers can contact buyers, sellers, listing agents, selling agents, or review closing documents when available. The goal is confirming the sale conditions, any financing concessions, and the property's physical characteristics.
The Verification Requirement
Here's where things get strict. If someone with a financial interest in your transaction provides comparable sales data, the appraiser must verify that information through an independent source.
Let's say your real estate agent gives the appraiser information about a recent comparable sale down the street. Since your agent has a financial interest in your transaction closing, the appraiser cannot rely solely on that information. They must verify the sale details through someone who doesn't benefit from your loan — perhaps the other agent involved in that comparable sale or through public records.
This rule prevents conflicts of interest and ensures the appraiser gets accurate, unbiased information about comparable sales.
Sales History Requirements
Fannie Mae requires specific timeframes for sales history reporting. Your appraiser must research and report any sales of your property within the past three years. For the comparable properties they use, they need to report sales within the past twelve months.
This sales history helps identify potential red flags. If your property sold six months ago for $200,000 and you're now buying it for $350,000, the appraiser needs to understand and explain that price jump. Was there a major renovation? A distressed sale situation that's now resolved? Market appreciation? The sales history provides crucial context.
The same applies to comparable properties. If a comparable home sold twice in the past year with dramatically different prices, that affects how useful it is for determining your property's value.
Why These Rules Matter
Fannie Mae requires this thorough analysis because real estate markets can shift quickly, and incomplete information leads to inaccurate valuations. In stable markets, recent closed sales might tell the whole story. But in changing markets, you need the complete picture.
Consider a neighborhood where prices have been declining. Looking only at sales from three months ago might overstate current values. But if you also examine recent contract sales and current listings, you might see that buyers are now negotiating prices 5% below those older sales. That information is crucial for an accurate appraisal.
The verification requirements exist because mortgage fraud often involves inflated comparable sales data. By requiring independent verification, Fannie Mae reduces the risk that someone manipulates the appraisal process.
Common Issues and Complications
Markets with limited sales activity create challenges for appraisers. In rural areas or unique property types, finding truly comparable sales within the required timeframes can be difficult. Your appraiser might need to expand their search area or use older sales with appropriate adjustments.
New construction areas present another complication. If your neighborhood is still being built, there might be few closed sales but many contract sales and listings. Your appraiser must carefully analyze this data to determine whether contract prices reflect current market conditions or represent pre-construction pricing that no longer applies.
Distressed sales can skew the analysis. If several foreclosures or short sales occurred recently in your area, your appraiser must determine whether these represent the current market or unusual circumstances. They might need to give more weight to non-distressed sales or make adjustments to account for the different sale conditions.
Properties with unique features face additional scrutiny. If your home has a pool and most comparable sales don't, or if you have a large lot in an area of smaller lots, the appraiser must carefully adjust for these differences. The sales comparison approach works best when properties are truly similar.
References
For the official guidelines, see B4-1.3-07: Sales Comparison Approach Section of the Appraisal Report in the Fannie Mae Selling Guide.
Mortgage guidelines change. Stay current.
Fannie Mae and Freddie Mac update their rules several times a year. Get notified when changes affect your mortgage eligibility, required documents, or loan terms.
No spam · Unsubscribe anytime
Original Fannie Mae Guideline Text
B4-1.3-07, Sales Comparison Approach Section of the Appraisal Report (06/04/2025)
Overview
Data and Verification Sources of Comparable Sales
Prior Sales History of the Subject and Comparable Sales
Uniform Appraisal Dataset (UAD) 3.6 Policy
Overview
The sales comparison approach to value is an analysis of comparable sales, contract sales, and listings of properties that are the most comparable to the subject property.
The appraiser’s analysis of a property must take into consideration all factors that have an effect on value. The appraiser must analyze all closed sales, contract sales, and offerings or listings of properties that are the most comparable to the subject property in order to identify any significant differences or elements of comparison that could affect their opinion of value for the subject property as of the effective date of the appraisal report. This is particularly important in changing (increasing or declining values) markets. Analyzing closed sales, contract sales, and offerings or listings is an important analysis in any market and will result in more accurate reporting on market conditions, including trends that indicate that sale prices for contract sales and asking prices for recent offerings or listings have changed. (Also see B4-1.3-03, Neighborhood Section of the Appraisal Report, for information regarding Trend of Neighborhood Property Values, Demand/Supply, and Marketing Time.)
Data and Verification Sources of Comparable Sales
Data and verification source(s) for each comparable sale must be reported on the appraisal report form. Examples of data sources include, but are not limited to, a multiple listing service, deed records, tax records, real estate agents, builders, appraisers, appraiser’s files, and other third party sources and vendors. The appraiser must state the specific data source (such as tax records or deed records), and refrain from using broad categories, such as “public records.” Data source(s) must be reliable sources for the area where the subject property is located.
Examples of verification sources include, but are not limited to, the buyer, seller, listing agent, selling agent, and closing documents in certain situations. Regardless of the source(s) used, there must be sufficient data to understand the conditions of sale, existence of financing concessions, physical characteristics of the subject property, and whether it was an arms-length transaction.
It is acceptable to obtain comparable sales data from parties that have a financial interest in either the sale or financing of the subject property; however, the appraiser must verify the data with a party that does not have a financial interest in the subject transaction. For example, if the real estate agent of the subject property has provided comparable sales data, that information must be verified through another disinterested source.
Prior Sales History of the Subject and Comparable Sales
Fannie Mae’s appraisal report forms require the appraiser to report the three year subject property and twelve month comparable sales history.
Uniform Appraisal Dataset (UAD) 3.6 Policy
Lenders using UAD 3.6 must follow the requirements in the UAD 3.6 Policy Supplement.
