Why is your California home's value a range, not one exact number?

Market value is a forecast, not a price tag

Here is the official definition, used in federal banking rules (12 CFR 34.42) and in Fannie Mae's Selling Guide. Market value is the most probable price a property should bring in a competitive and open market, with a buyer and seller each acting prudently and knowledgeably, and the price not affected by undue stimulus.

Read that first part again. Most probable. Not guaranteed. Not the highest. A weather forecaster who says 70% chance of rain is not wrong when it stays dry. A value works the same way.

The definition also lists conditions. The buyer and seller are typically motivated. Both are well informed or well advised. The home gets a reasonable time on the open market. Payment is cash or normal financing, with no special or creative financing or concessions bending the price. And it assumes a sale as of a specified date. Change the date and you have a different question.

Real sales rarely meet every one of those conditions perfectly. That is part of why the answer is a band.

Why real buyers don't all pay the same

Put the same house on the market on ten different weekends and you would likely get ten different winning offers. Not because the house changed. Because the buyers did.

• One buyer needs that school and will stretch for it.
• One has a boat and only cares about the side yard.
• One hates stairs and walks out of every two-story in the area.
• One is relocating and needs to close in three weeks, so she stops shopping early.
• One saw the house on a rainy Tuesday when the street was empty. Another saw it on a sunny Saturday with three other cars out front.

Add how many buyers happen to be looking that month, what rates are doing, and whether a seller credit is in the deal, and the closing price can land anywhere in a reasonable band.

That's not a flaw in the market. That is the market. Your neighbor's sale is one draw from that band, which is why it is a great comp and a bad price tag.

Where the range comes from in an appraisal

An appraiser picks the most similar recent sales, then adjusts each one for real differences: size, condition, lot, location, and the market's movement since it sold. Each adjustment is measured from paired sales and checked against the wider market. After that, each sale says what your house would have sold for. Those answers form the adjusted range.

Here is a hypothetical, a 1970s two-story in Pleasanton. Every number below is made up to show the method.

The adjusted range runs from $1,601,000 to $1,672,000. That band is the evidence. A tight band means the sales agree. A wide band means the data is thin or the house is unusual, and the report should say which.

Fannie Mae's rules say the value from the sales comparison approach must fall within the range of the adjusted sale prices. They also say reconciliation must never be an averaging technique, unless a weighted average comes with a proper explanation.

Why the appraisal still names one number

A lender has to lend against something. The standard lender report, Fannie Mae Form 1004, asks for the appraiser's opinion of market value as one dollar figure, as of one effective date. For a purchase, the lender then uses the lower of the sale price or that appraised value.

Outside of lending, the rules are looser. In a 2010 letter, the Appraisal Subcommittee, a federal agency, quoted the national appraisal standards (USPAP) as allowing an opinion of value to be stated as a specific amount, a range of numbers, or a relationship to a benchmark.

So how do you get from a band to a point? In the hypothetical above, I might land at $1,650,000. Sale 1 needed the smallest adjustments and is the same model in the same tract. Sale 5 is the freshest read on the market and sits at the top. Sale 4 needed a location adjustment, so it gets less say. The result sits inside the range, near the strongest evidence. Notice it is not the simple average, which would be $1,642,600.

Weighting is one way to do that. Judgment across the adjusted range, with the reasons written down, is another. Either way, the reasons belong in the report. I go deeper on this in how appraisers land on one final number.

One thing never picks the point: the contract price. The evidence has to stand on its own.

How sellers and agents should use the range

1. Ask for the range along with the number. If someone gives you one figure with no band, ask how far apart the adjusted sales were.
2. Decide where you want to start. Pricing near the low end usually means more buyers and more showings. Pricing near the top needs the best condition on the street and some patience.
3. Read the market in real time. Check whether the last 30 to 45 days of sales sit higher or lower than the band. A year-long average can hide a turn.
4. Read pending sales at a predicted close. Multiply the asking price by the measured sale-to-list ratio for similar homes. See how to read pendings.
5. Set your walk-away number before offers come in. The range tells you what a fair deal looks like, so you're not deciding in a panic at 9 p.m.
6. Know the ceiling. An offer well above the top of the range may not appraise. Plan for that before you accept it.

What I see in the field

Sellers hear the top of the range. Buyers hear the bottom. Everyone hears a different number from the same sentence. That is why I put the band and the reasons in writing.

A range is not a menu. You don't get to pick the top because you like it. Where a home lands inside the band depends on how it compares with the best sales, and the report should say why.

The width of the range is information too. A tight band in a big tract tells you the market has spoken clearly. A wide band on a custom hillside home tells you to be careful with anyone who sounds too sure.

And online estimates? Even the ones that show a range never walked through your kitchen. They are a reason to ask questions, not evidence. A guess with a decimal point is still a guess.