In a separate analysis, Zillow found that sellers who never put their homes on the Multiple Listing Service (MLS) — the shared database agents use to advertise homes for sale — lost $1.36 billion over the same years.
Before you treat those numbers as a sure thing, keep two points in mind. First, Zillow has skin in this game. It sued brokerage Compass and a Chicago-area listing service over private listings just two days before it released a study that says those listings cost sellers money. Second, an independent economist warned that these estimates lean on some big assumptions.
That said, this wasn’t a one-year fluke. Sellers took the same hit in all three years Zillow studied. So it’s worth paying attention since there are ways you can protect yourself before signing anything.
Why one agent on both sides can cost you money
Zillow analyzed more than 15 million home transactions from 2023 to 2025. Of the home sales it looked at, 4.7% were dual agency transactions, meaning one agent represented both the buyer and the seller. California sellers lost the most, an estimated $533 million in total. Florida sellers lost $217 million, New York sellers $146 million and New Jersey sellers $115 million.
According to Zillow, the economic incentive of agents shifts when they represent both the buyer and the seller. The additional commission that comes from pushing a seller’s price up is small. But the potential cost of selling to a different buyer and splitting the commission with another agent is high. This can cause agents to close deals with buyers regardless of whether it’s in the best interest of the seller.
“Sellers deserve an agent whose only job is to get them the best possible price, and a listing that every buyer in the market can see,” Zillow Chief Economist Mischa Fisher said in a press release.
Why Zillow’s estimates come with an asterisk
Zillow compared each sale price with its own estimate of what the home was worth, the Zestimate, from three months earlier, and adjusted for local price changes. Then it checked what the home actually sold for. Homes bought and sold by the same agent came up short, and Zillow spread that gap across millions of sales to land on $1.49 billion.
So the total rests on a few big ifs. It assumes the Zestimate got the value right. It also assumes the shortfall came from the agent setup, not from the house being a fixer-upper or the seller wanting a fast sale.
That’s what bugs Paul Carrillo, an economics professor at George Washington University who had no part in the study. He told RISMedia the findings track with what economists would expect. He’s more careful about the big dollar totals, though, because “we need to make very strong assumptions to get to those numbers.”
One more thing worth knowing is that Zillow has filed a lawsuit against the Midwest Real Estate Data (MRED) and Compass over allegations they are colluding to hide home listings from buyers.
