Compass Research on Zillow Listings Draws Scrutiny Over Methodology

Compass Research on Zillow Listings Draws Scrutiny Over Methodology

A recent analysis by Compass, Inc. has sparked a debate within the real estate industry regarding the financial impact of listing homes on major portals. The study, which Compass labeled the “Zillow tax,” asserted that properties displayed on Zillow sold for 1.3% less than homes that were banned from the platform. However, the findings have faced significant criticism regarding the methodology used to calculate the purported loss.

The report examined 296,966 Compass listings between January 2025 and May 2026. According to the release, 806 of these listings were banned by Zillow Group, Inc., while the remainder appeared on the site. Compass reported that banned homes sold for 100% of their asking price, whereas those on Zillow sold for 98.7%. The company applied this percentage difference to the price of a typical American home to arrive at a figure of $5,590, framing it as a cost to the seller.

Critics, including various economists, have challenged the validity of this comparison. The core argument is that comparing the percentage of the asking price achieved does not necessarily reflect the total net proceeds for the seller. Since the asking price is determined by the listing agent rather than an external market metric, the comparison may reflect pricing strategy rather than platform performance.

For example, if two identical homes are valued at $1 million, a home listed at $1 million and selling for $987,000 achieves the 98.7% ratio cited by Compass. However, a second home listed at $950,000 that sells for the full asking price achieves a 100% ratio, yet leaves the seller with $37,000 less in gross proceeds. Because Compass agents control the asking prices on both sides of the study’s comparison, critics argue the data lacks an independent control variable.

Establishing whether limited exposure affects the final sale price typically requires comparing actual sales against estimated values or appraisals. Previous analyses, such as those conducted by Zillow regarding off-MLS listings, have utilized estimated values to measure the difference in sale proceeds. The discrepancy in methodologies highlights the difficulty in isolating the effect of portal visibility from listing agent pricing decisions.

In market activity, Compass shares were up 2.98% to $11.57, while Zillow shares rose 1.12% to $34.38.

What to watch

• Future independent studies comparing off-MLS sales against automated valuation models (AVMs).
• Responses from real estate economists regarding listing exposure data.
• Guidance from Compass regarding marketing strategies and platform utilization.

Source: original release