CMA vs Appraisal vs Zestimate: Why Your San Antonio Home Has Three Different Prices

Three different people can look at your house in Stone Oak on the same afternoon and give you three different prices. A SABOR agent pulls a CMA and says $412,000. Zillow's Zestimate says $438,500. Six weeks later the buyer's lender sends an appraiser and the report comes back at $395,000. None of them are lying. They are answering different questions with different data, and in Texas the gap between them is wider than almost anywhere else in the country.

If you are about to list, you need to understand which number drives the contract price, which one kills the deal at the financing contingency, and which one you should ignore entirely.

Three numbers, three different jobs

• CMA (Comparative Market Analysis) — built by a licensed agent using the SABOR MLS. Its job is to predict what a ready buyer will sign on a TREC 20-17 contract in the next 30–90 days. Forward-looking. Incorporates active competition, pending sales, and condition.
• Appraisal — ordered by the buyer's lender after the contract is signed, performed by a state-licensed appraiser on a Uniform Residential Appraisal Report (Form 1004). Its job is to protect the lender's collateral. Backward-looking. Uses closed sales only, usually within the last 90 days and within one mile.
• AVM (Zestimate, Redfin Estimate, Realtor.com estimate) — an algorithm fed by public records. Its job is to generate a lead, not to price a house. It has never been inside your home.

These are not three opinions of the same thing. They are three different instruments measuring three different things.

Why Texas non-disclosure breaks the Zestimate

Texas is one of about a dozen non-disclosure states. When a home sells in Bexar County, the sale price is not recorded with the deed at the county clerk. BCAD (the Bexar Appraisal District) has to reconstruct market values for tax purposes using surveys, voluntary disclosures, and MLS data they negotiate access to — and their numbers lag the real market by roughly a year.

Zillow's algorithm relies heavily on public-record sale prices. In California or Florida, those records are complete and current. In Texas, they're partial. The Zestimate is effectively guessing at the inputs its own model was designed to use. That is why you will see:

• A renovated 1940s bungalow in Mahncke Park (78209) Zestimated at the same price as an unrenovated one two blocks over, because the algorithm cannot see that the kitchen was gutted last year.
• A Stone Oak tract home in a gated section valued identically to the same floor plan on a busy street, because the algorithm does not weight the HOA boundary or the pole easement in the back yard.
• Values that swing $20,000 overnight when a single comp finally hits the public record six months late.

Treat AVMs as a rough sanity check, not a price. If your agent's CMA and the Zestimate disagree by 8%, the Zestimate is almost always the one that is wrong.

How a real CMA gets built

A competent San Antonio listing agent is not pulling "three comps in your ZIP." A defensible CMA for a $400,000 home in, say, Alamo Ranch (78253) off Loop 1604 west looks like this:

1. Define the competitive set. Same school attendance zone (Northside ISD elementary boundaries can split a subdivision in half and move $15/sf), similar square footage band (±15%), similar age cohort, same general product type.
2. Pull closed sales from the last 90–180 days. Six months is the outer edge. Older than that and you are pricing to a market that no longer exists.
3. Pull active and pending listings. Actives tell you what you are competing with this weekend. Pendings tell you what buyers actually wrote on in the last 30 days — the freshest signal you can get.
4. Adjust line by line. Pool (+), backs-to-greenbelt (+), backs-to-1604 (−), no primary down when buyers in that tract expect one (−), updated primary bath (+), original 2004 carpet (−).
5. Bracket a list price. A good CMA produces a range, not a point. $398,000–$415,000, with a recommended list based on how aggressive the seller wants to be.

If your agent hands you a one-page printout with five comps and a single number at the bottom, you got a Zestimate with a logo on it.

What the appraiser does differently

The appraisal happens after the contract is signed under a TREC 1-4 Family Residential Contract (Resale). If the buyer is financing and the appraisal comes in low, the Third Party Financing Addendum controls what happens next — typically renegotiation, a TREC 39-9 Amendment, or termination.

Appraisers work under tighter rules than agents:

• Closed sales only. Pendings and actives are context, not comps.
• Distance and time limits. Fannie Mae guidelines push appraisers toward comps within one mile and 90 days. In a fragmented market like San Antonio — where 78209 (Alamo Heights / Terrell Hills) sits next to 78218 (Northeast Side) with a $150/sf gap across a single street — that one-mile rule can force weird comp choices.
• Grid adjustments. Every difference between subject and comp gets a dollar adjustment, and the total net and gross adjustments have caps. An appraiser cannot stretch to reach the contract price the way an agent can stretch to reach a list price.
• Condition is rated C1–C6. A C3 (well-maintained) versus a C4 (adequate, some deferred maintenance) can swing the value materially, and the appraiser decides, not you.

Appraisers are also human, and appraiser quality in Bexar County varies. A San Antonio appraiser who works the central corridor every week will price an Olmos Park Tudor correctly. An appraiser assigned out of a national AMC rotation who drives in from Austin may pull a comp from the wrong side of US-281 and miss by $25,000.

When the three numbers diverge most

Scenario	CMA	Appraisal	Zestimate
Recently renovated home	Accurate	Lags — needs closed comps of other renovated homes	Badly low
Rapidly rising submarket (e.g. Southtown 78204)	Ahead of appraisal	Behind by 60–90 days	Wildly variable
Unique property (acreage in Helotes, historic King William)	Wide range, agent judgment	Often low — no true comps	Essentially meaningless
Tract home in active subdivision (Alamo Ranch, Cibolo)	Tight range	Close to CMA	Usually within 5%

The tighter and more homogeneous the neighborhood, the more the three numbers converge. The more unique the property, the more you should weight the CMA and ignore the AVM entirely.

What most people get wrong

• Pricing off the Zestimate. It is a lead-generation tool. It is not evidence. Do not walk into a listing meeting insisting on a number because Zillow said so.
• Assuming BCAD's assessed value equals market value. It does not. Assessed value is capped at 10% annual growth on a homesteaded property under Texas Property Code § 11.13, and BCAD's data lags the market. A house assessed at $340,000 can absolutely sell for $420,000.
• Listing at the top of the CMA range "to leave room to negotiate." In San Antonio, the first two weeks on market get the most traffic. Overpriced listings sit, then chase the market down. The buyer who would have paid $410,000 in week one will offer $385,000 in week six because your days-on-market now reads as desperation.
• Ignoring the appraisal risk before you accept an offer. If you accept $435,000 on a house your agent's CMA capped at $415,000, understand the appraisal is likely to come in below contract. Plan the response before you sign the TREC 20-17, not after.
• Treating the Seller's Disclosure (TREC OP-H) as unrelated to price. Under Texas Property Code § 5.008 you must disclose known material defects. A foundation repair disclosed up front prices into the offer. The same repair discovered at inspection becomes a renegotiation, and you lose more than if you had priced correctly from day one.
• Hiring the agent with the highest suggested list price. That is a sales tactic, not a pricing opinion. Ask every agent you interview to walk you through their comp selection and adjustments. The one who can defend the number is the one to hire.

Where to go from here

If you want a CMA built by a San Antonio agent who will actually show their work — comp by comp, adjustment by adjustment — you can connect with one through /agents on RentInSA. If you are selling without an agent, the FSBO listing at /list-your-home is free, and the rest of the seller playbook lives at /resources.