Home sellers get the shaft when just one real estate agent plays both sides of the deal, according to stunning new Zillow data.

The estimated loss per home from sellers in these dual-agency transactions is about $2,165. 

“We encourage each buyer to have their own broker, but many buyers today think they’ll get a better deal using the seller’s broker only,” said New York City broker Barbara Fox with Brown Harris Stevens. This just isn’t so.”

All told, sellers in these one-agent deals lost a combined $1.49 billion over the past three years.

“The additional commission earned from pushing a seller’s price up is generally modest, while the potential cost of selling to a different buyer and splitting a commission with another agent is significant,” Zillow’s report says. “That dynamic can incentivize certain agents to close a deal with a buyer they represent rather than negotiate hard for the maximum sale price.”

The problem is greatest in California, with sellers in dual-agency deals losing an estimated $533 million over the study years of 2023, 2024 and 2025. New York sellers lost $146 million. 

“A lot depends on the quality and integrity of the representation,” said Douglas Elliman’s Chris Wands, who is based in Miami. “Unfortunately, not every agent in the industry operates the same way.” 

Another costly mistake home sellers can make is listing privately, or off the Multiple Listing Service (MLS). That resulted in a $4,230 typical loss per person, or a combined loss of $1.36 billion over three years, with the homes typically going for 1.3% less than sellers who listed publicly. 

“This has become a huge issue in our New York City marketplace unfortunately,” Fox said. “The only people that benefit from ‘private’ listings, where a broker holds a listing within his/her own firm for a period before offering it to the public and to the remainder of the brokerage companies, are the listing broker and their company — certainly not the seller.” 

Sellers in New York state left $135 million on the table when selling privately between 2023 and 2025, a spokesperson for Zillow told The Post.

“The more buyers who have eyes on a property, the better chance you have of creating competition, and competition is usually what drives pricing,” Wands said. “In the middle market especially, MLS exposure is one of the most important tools sellers can use to maximize visibility and generate demand.”

But, he cautioned that the data doesn’t always fit at the upper tier. “In the luxury market, there are situations where privacy, timing, discretion or buyer quality matter more than just maximizing exposure,” Wands said.

Some other seller mistakes include: 

• Ignoring your “screen appeal,” per Zillow’s spokesperson. “Most people start their search online, so screen appeal is the new curb appeal. Make sure your listing stands out.”
• Mispricing your home. “We’re seeing a growing gap between homes that sell fast and others that linger — roughly one in five homes nationwide is selling within a week, but the average home on the market is sitting longer,” the rep said. “Getting your pricing right from the start is key.”
• “Hiring an agent based solely on the highest suggested list price rather than strategy and execution,” Wands said.
• Listing the home at the wrong time. “Timing and understanding current buyer sentiment within a specific market segment also matter much more than many sellers realize,” Wands said.