There are many reasons behind Spain’s surging property market, but some experts say the very search engines we use to house hunt – including Idealista and Fotocasa – could actually themselves be contributing to price rises.
The Spanish property market has experienced soaring prices in recent years.
A supply shortage combined with an increase in tourist apartments and skyrocketing demand, plus an influx of wealthy foreigners, has seen the price of property rise in the post-pandemic period for both rentals and purchases.
According to the latest data published by Eurostat, the year-on-year increase in house prices across EU countries stood at 5.5 percent in the final quarter of 2025, while in Spain it was 12.9 percent — the fourth highest in the EU.
Many Spanish cities have also seen eye-watering rental price rises.
For many on the house hunt in Spain, property websites like Idealista and Fotocasa, two of the best known in Spain, are therefore very familiar. But could they actually be contributing to the price rises themselves?
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Reporting in the Spanish press suggests that the algorithms used by these housing portals could encourage unfair competition, favouring corporate networks and large-scale property owners over small private individuals, something that pushes prices up overall.
One of Spain’s political parties certainly believes so.
Far-left junior coalition partner Sumar recently put a motion before Congress directed at both Idealista and Fotocasa. The proposal seeks to ensure greater transparency and regulation, notably to establish a body within Spain’s National Commission for Markets and Competition (CNMC) to monitor the effects of AI on the housing market.
It submitted a request for a representative from each platform to appear before the Committee on Economy, Trade and Digital Transformation. Specifically, they want to speak to María Matos, Director of Research and spokesperson for the Fotocasa portal, and Pablo Álvarez-Cascos, Director of Technology at Idealista Contexto.
Both are figures regularly cited by Spanish media and The Local.
Experts say these algorithms could have an influence on house price trends, promote unequal competition between small-scale landlords and large property owners, and, ultimately, on the ability of thousands of families to access the market.
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Critics claim the algorithms on these sites cause them to display prices significantly higher than the notarial valuation, that is, their actual economic value.
In the long term, this can feed a price bubble that further restricts access to a market already strained by property speculation and rising prices.
As such, the properties listed for the user are priced above market value, and this inflated, standardised price is used as the basis for future listings.
READ ALSO: The overlooked factors causing Spain’s housing crisis
Spanish left-wing news website El Salto claims the sites also weigh the data according to the number of listings rather than by geographical area, which could also create significant price gaps.
El Salto also claims that property listings published on websites such as Fotocasa and Idealista show prices up to 44 percent higher than the average values declared before a notary.
Más Madrid MP Tesh Sidi, one of the representatives who tabled the motion in Congress, said: “Idealista’s artificial intelligence algorithm is not updated according to those actual sales figures because the government publishes them months later. Therefore, the algorithm is not corrected with the actual data; in other words, it sets the sales figure on the portal as the base price and does not adjust it over time.
“Consequently, when another user goes to buy a flat in that same area, the price at which user X bought it is set as the baseline”.
In doing so, Sumar says, both portals are failing to comply with European and Spanish regulations on transparency.
“When the filter is based not on your interests, but on those of the platform owner, we are no longer talking about a recommendation, but about manipulation that influences a consumer’s decision,” Borja Adsuara, Professor at the Universidad Complutense de Madrid and expert in digital strategy and communication, told Público.
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“It was already prohibited under the Unfair Competition Act and the General Advertising Act. Well, the same now applies to algorithms,” he adds, referring to a ban established in the European Union’s Digital Services Act which was passed early last year.
But there are other ways to tinker with the algorithm.
“You can also pay to enhance your photos or have new ones taken, which can similarly improve your advert’s ranking on the website,” Adsuara adds.
Another option is to use one of the property valuation services or estate agency booking services offered by the portal itself.
All of these techniques come with the same idea: more interactions, more visitors, and more purchases.
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These companies, of course, deny the charge.
Tony Blamey, CEO of Fotocasa Group, told Spanish daily El Mundo in a recent interview that although he “can understand why there are debates, because housing is very important to people and supply is limited”.
However, he argued the site gives users more control. “The discussion about algorithms and price is not real. Our algorithm does not work like that. We give control to the user, who filters by price,” he added.
READ ALSO: What will it take for property prices to start going down in Spain?
