Atherton, California Overtakes Miami's Fisher Island as Nation's Costliest ZIP Code

Atherton, California's 94027 ZIP code has displaced Miami's Fisher Island 33109 as the United States' most expensive postal area, driven by a surge in AI-related wealth.

Atherton, a Silicon Valley suburb in San Mateo County, reclaimed the title of the nation's priciest ZIP code, overtaking Miami's Fisher Island for the first time in two years. PropertyShark's latest rankings indicate the median home price in 94027 reached almost $10 million in the first half of 2026, up about 20% from the previous year. The boom is fueled by AI executives and engineers cashing in on stock gains, prompting at least five home sales above $30 million this year.

Fisher Island's rise had been powered by finance moguls such as Ken Griffin, Jeff Bezos and Carl Icahn, who drove Miami-Dade property values to record highs during the pandemic exodus. Though now second, Fisher Island still hosts exclusive condos and mansions, some listed near $85 million, and offers private beaches, a golf course and a country club. The real-estate reshuffle underscores a broader transition in where extreme American wealth is generated, shifting from traditional finance to the burgeoning AI sector.