Google appears to be running tests on putting real estate sale listings into its search results. Over the weekend, real estate tech strategist Mike DelPrete published mobile phone screenshots of Google Search results showing real estate listings, which appeared to be powered by real estate data company HouseCanary. The listings enabled users to view the full details of a property’s page, request a tour and contact an agent — similar to the functions offered on Zillow.com’s online marketplace portal. Google’s home searches appear to work only in select markets and on mobile devices as testing is underway.

The decline in Zillow signals investors are bracing for the eventual impact of Google’s foray into the real estate market. The company, which saw shares drop more than 11% at one point during Monday’s session, lost about $1.6 billion in market cap. Zillow’s market cap now sits at about $16.26 billion.

However, Wall Street analysts were quick to point out that Zillow’s exposure to organic search is fairly small, limiting potential downside at least in the near term as more details around Google’s product come to light.

Wells Fargo analyst Alec Brondolo, who has an equal weight rating on Zillow, said he would not “expect a meaningful financial impact from listings on Google shifting from organic to paid” — given that Zillow is not overly dependent on organic search results for traffic.

“The listings product appears similar to Google Hotel Metasearch results; introduction could increase traffic cost to Zillow, but disintermediation unlikely,” Brondolo said in a Monday note to clients. “In the hotel category, Google merchandises hotel rooms in search results as a metasearch ad product for OTAs. We would expect a similar approach in real estate, with Zillow, Homes.com, Realtor.com, etc. bidding for home listing ad units rather than Google attempting to monetize directly with an ad product sold to agents.”

But some analysts see Google’s testing as a longer-term headwind to Zillow and other online real estate portals.

Goldman Sachs’ Michael Ng wrote in a note to clients that he believes the search engine’s real estate listings, which he said are an advertising format for buy-side agents, directly compete with Zillow’s Premier Agent program by “facilitating lead generation” for agents from prospective buyers.

“While we don’t expect a direct near-term impact on Zillow’s business, given that most of Zillow’s traffic is direct (e.g., Zillow.com, StreetEasy.com, mobile apps) and Google’s new product is currently limited to select markets and mobile browsers, we view this development as a long-term risk for real estate portals like Zillow,” Ng, who remains neutral on Zillow, wrote in a note to clients.

Jason Helfstein of Oppenheimer said that Google’s expansion into real estate could impact the number of consumers going to Zillow.com — which was 228 million in the third quarter — and therefore could take a hit on the company’s ability to monetize its platform. “The impact would likely take years to play out and would need to be rolled out across the US to meaningfully impact real estate portal traffic,” Helfstein said in a recent note.

Zillow shares are down more than 8% year to date.

Neither Google nor Zillow responded immediately to CNBC’s request for comment.

Actor-entrepreneur Mark Wahlberg paid $37 million for a fully furnished mansion in Delray Beach, Florida, last month. The deal piqued interest and prompted coverage from TMZ to Architectural Digest, with most of the focus on the celebrity buyer.

But aside from the name recognition, the home’s skyrocketing price over the past five years also makes it stand out.

The actor’s transaction in October marks the home’s fourth sale in that same time period, and a dramatic 118% price increase from its sale in January 2020 when the fully furnished mansion traded for $17 million.

The estate, located at 9200 Rockybrook Way, saw a rise in value that outpaced not just the local market, but also many of the top luxury markets in America.

In Delray Beach, the average sale price for a single-family luxury home, represented by the top 10% of closed sales, rose by just over 78%; Los Angeles was up 30%; the Hamptons rose 44%; and Manhattan increased just 4.5% according to Elliman Report data from the first quarter of 2020 to the third quarter of 2025.

The home’s steep rise in value even outperformed the S&P 500, which was up about 100% over the same time period.

Remarkably, the residence has traded hands four times since 2020. Just one real estate broker represented the listing in all four transactions, making the soaring value of the seven-bedroom, 10-bath mansion even more unique.

Back in 2020, Douglas Elliman real estate broker Senada Adzem represented the original owners of 9200 Rockybrook, when the house was known as the Sundara estate. Three years later, Adzem represented the mansion’s second owners who listed the home again, when it sold for $26 million, up 53% in just three years.

A little over a year after buying the place, public records show a trust connected to William Cafaro, the co-president of a retail property development company in Niles, Ohio, and the home’s third resident decided to sell. Adzem was once again the listing agent.

This transaction was more unusual. Cafaro sold the home as part of a larger $50.5 million deal to purchase a Ferrari-inspired mansion less than half mile up the road in Stone Creek Ranch. Casa Maranello, as it’s known, was being sold by local developer Aldo Stark, of Prestige Design Homes, with Adzem as the listing agent.

Cafaro paid for the new home with $24.5 million in cash, plus the deed to 9200 Rockybrook Way, which was valued in the deal at the same price he’d paid for it: $26 million. 

When that sale closed in January 2025, Stark became the fourth owner of the mansion and he immediately started a dramatic multimillion-dollar renovation of the almost 17,800-square-foot megahome. He scrapped the old Sundara name and clad the home’s old sheet-rocked walls in polished rare stones and bold high-gloss Guyana wood from Brazil.

He installed vibrant green vegetation above a grand stairway and into the ceilings.

Stark completely reimagined everything from the kitchen to the clubroom and filled the residence with bespoke furniture.

And about two moths after closing, the megahome was listed for sale for a fourth time.  

Reemerging with a new look, new name and a new price tag, one of the few things to remain the same was that Adzem was once again the listing agent.  

The home, now called Palazzo di Lago, debuted with an ambitious $45 million asking price, $19 million more than what Stark paid for it two months earlier and 165% more than what it sold for in 2020.

By October Adzem closed the fourth deal and delivered Palazzo di Lago to its fifth owner, who the buyer’s broker, Michael Costello of Compass, confirmed to CNBC was Mark Wahlberg.

According to Florida’s Multiple Listing Service, the fully furnished mansion closed at $37 million, $11 million more than what Stark bought it for seven months earlier, and up 118% from its 2020 sale. 

And Adzem pulled off an uncommon feat in real estate, selling the same house four times in five years in transactions totaling $106 million.

Five owners across five years seems like an unusually high turnover rate, but Adzem has a simple explanation.

“People’s circumstances change and they have different chapters in their life. So we were privileged to be able to guide this home through different evolutions and different owners and be able to add value to it,” Adzem said.

According to Adzem, the mansion’s remarkable appreciation was fueled by a multitude of factors. Here are the top five:

1. The pandemic

Adzem attributed a large part of the 53% rise in price from 2020 to 2023 to the pandemic, which made demand and prices for homes in South Florida surge.

“After Covid, our market definitely accelerated,” she told CNBC.

2. The ‘micro-market’

Some of the other market dynamics driving the price of Palazzo di Lago are unique to Stone Creek Ranch, which Adzem described as a luxury “micro-market.”

The exclusive gated community spans about 187 acres with 37 luxury homes each on about 2.5 acre lots. It’s a tight supply that’s seen pricing dramatically impacted by a wave of new construction homes that have traded at record-breaking prices. Those recent comps helped push the price of Palazzo di Lago higher.

Even the price of dirt in Stone Creek Ranch is on a steep rise. Back in 2013, the empty lot at 9200 Rockybrook Way traded for $800,000. In 2021, Adzem sold a comparable 2.5-acre lot for $1.7 million.

“The last one they traded was $6 million,” Adzem told CNBC. “However … there are no vacant lots left in this community.”

And Adzem believes a more than threefold rise in the price of dirt here is just the beginning. She points to the fact that 2.5-acre lots worthy of a megahome are hard to come by in Palm Beach County, and the dwindling supply in this neighborhood in particular will push lot prices even higher. 

“I feel like the dirt is going to double because the only upcoming potential sales would be teardowns.”

3. The power of VIP neighbors

Another market driver: the tiny community’s growing list of VIP owners.

In 2021, billionaire hedge fund manager and owner of the New York Mets, Steve Cohen purchased the home next door to 9200 Rockybrook Way for about $22 million, according to MLS.

″[Potential buyers] typically do look to know who else owns in the community. That’s important to them,” Adzem said. 

Rich and famous residents can create a halo effect and make nearby real estate more desirable to potential buyers. And there’s no shortage of ultra-high-net-worth neighbors living nearby, including several present and former CEOs of Fortune 500 companies, a former NFL player, and a pop star, according to Adzem and public records.

And now some might even see Walhberg’s new ownership as adding to the community’s allure. Meanwhile, developer Stark just finished construction and recently moved into his own 32,000-square-foot mansion.

4. Wealth migration

Wealthy buyers looking to escape the tax burdens of their home states continue to see the tax advantages offered in Florida as a big draw and that helps drive and sustain demand.

“We saw a big influx and continued influx of buyers from California, from New York, from Connecticut, and they want what you see here,” Adzem told CNBC.

5. The multimillion-dollar renovation

Adzem also credited Stark’s renovation with adding to the estate’s value.

“He didn’t go neutral and he didn’t go very light with color scheme. He really wanted to make an impact and put his own taste here,” Adzem said.

Adzem and Stark would only characterize the expense as “a multimillion-dollar renovation,” so it’s unclear exactly how much it took to turn a home built in 2017 into the new Palazzo di Lago.

But Adzem told CNBC the dramatic renovation and the new “James-Bond-inspired vibe” were the final catalysts that delivered a buyer willing to pay a premium.

Correction: William Cafaro paid for the new home with $24.5 million in cash. A previous version of this story omitted the million. The price of the home rose 53% from 2020 to 2023. An earlier version misstated the percentage.