Tech billionaire Mark Zuckerberg has sold his sprawling San Francisco home for US$31mil , more than tripling his money since reportedly buying the home for around US$10mil a decade ago.

The sale was confirmed by a deed filed with the city earlier this month, which was signed by an executive of the Facebook co-founder's eponymous Chan Zuckerberg Initiative.

The off-market sale of Zuckerberg's 21st Street home, which is situated on Liberty Hill near Dolores Park, was first reported by real estate news site The Real Deal. The US$31mil pricetag, calculated based on tax assessments cited in the deed, appears to be the most expensive home sale in San Francisco this year, edging out the US$29mil sale last week of two penthouse condos once owned by former Secretary of State George Shultz and his wife, former San Francisco Chief of Protocol Charlotte Shultz.

It's also the latest example of how tech magnates are growing their influence in global real estate, and how high San Francisco celebrity home prices can go. All told, Forbes reported that as of earlier this spring, the Bay Area was home to 116 of California's highest-in-the-nation 189 billionaire residents.

"Why does California reign supreme?" Forbes wrote in its April billionaire update. "Thank the booming technology industry."

The Shultz sale broke city records as the highest-priced condo sale in San Francisco history. Past industry reports note that at least one other San Francisco home, a house in tony Pacific Heights, previously traded for closer to US$40mil .

Despite the eye-popping sales figures, details about Zuckerberg's now-former house remain relatively scarce. The Dolores Heights house was purchased and sold by an entity listed as "SFRP LLC," which The Real Deal notes is also connected to a property owned by Zuckerberg in Palo Alto. The San Francisco house was purchased by an also-opaque Delaware LLC.

It was initially listed as a 7,200-square-foot, four-bedroom home, but famously underwent a renovation that attracted the ire of neighbours not so thrilled with the tech mogul's presence and construction noise. In 2016, some complained that Zuckerberg's security detail was hogging "desirable parking spots."

Fellow Silicon Valley magnates, including entrepreneur and venture capitalist Vinod Khosla, have courted controversy by buying up and attempting to privatise areas around Bay Area compounds. Others are also looking to cash out: Sun Microsystems co-founder Scott McNealy recently dropped the price on his Peninsula mansion to just under US$54mil .

In addition to his pricey Bay Area homes, Zuckerberg reportedly owns side-by-side US$59mil mansions on the Nevada side of Lake Tahoe, plus some 1,500 acres on the Hawaiian island of Kauai.

 - TNS