A Compass study found that listings posted on Zillow sold for 1.3% less than those not posted on the portal, which the brokerage referred to as the “Zillow tax.”
The study compared roughly 296,000 Compass listings on Zillow to 806 that were banned from the portal over a 15-month period.
Methodology and Results
The report concluded that the median sale-to-list price ratio for banned listings was 100%, versus 98.7% for listings on Zillow.
Additionally, 50.5% of banned listings sold at or above their list price, compared to 44.6% of listings on Zillow.
The study reviewed nearly 300,000 Compass listings between January 2025 and May 2026, with only 806 listings banned from Zillow’s platform.
Criticism of the Study
Experts have questioned the results, citing the vastly different sample sizes and limited study details.
Zillow Chief Economist Mischa Fisher called the study “unserious” and said it was an attempt by Compass to justify its commission-hoarding business model.
Sara Coers, director of the Indiana University Indianapolis Center for Real Estate Studies, said the analysis was “obviously a marketing piece” due to its flawed methodology.
Compass limited its study to listings affiliated with the brokerage’s agents, which may not be representative of the broader market.
Implications and Ongoing Dispute
The “Zillow tax” is estimated to cost home sellers thousands of dollars, with the report suggesting that homes priced at the median existing-home sale price of $430,000 would lose around $5,590.
Compass has been engaged in a long-running dispute with Zillow over the portal’s listing standards, which has led to some of the brokerage’s listings being excluded.
As the dispute between Compass and Zillow continues, it remains to be seen how the “Zillow tax” will impact the real estate market and home sellers.
Home sellers may start to consider alternative marketing strategies, such as phased marketing, to avoid potential losses.
However, the benefits of listing on Zillow, such as increased exposure, may outweigh the potential costs.
Time on market was not significantly different for the two sets of listings, according to the report.
Compass Chairman and CEO Robert Reffkin said the information Zillow publishes about a home contributes to its devaluation.