"This house looks as if it needs remodeling now, but that's because it's been torn apart. It actually was not in that bad a shape when it was bought," said Van de Mark. He talked about the property outside the house, as contractors were fixing it up.
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Van de Mark said Zuckerberg "has submitted permits for about $1.6 million worth of upgrades, repairs, remodeling. But that isn't the real number. Everyone always goes in and submits numbers that are going to be less than what the real cost is, because then you keep your tax rate down."
According to Van de Mark, the remodeling could cost more than $4 million to $5 million.
A Multiple Listing Service of the property said it was sold for $1,200,000 on Jan. 9, 1997. In that MLS document, the assessed value of the home and 7,980 square foot lot in 2012 was $1,559,572. That's far, far less than the latest price tag of $9,999,999.
The Dolores Heights home was purchased through a legal entity known as SFRP LLC. The main beneficiary is Cary S. Collins, according to public records.
Neither Zuckerberg nor a personal representative could be located for comment by CNBC. A Facebook representative said: "We don't comment on Mark's personal life."
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By any measure, Zuckerberg is on a roll. He was America's highest-compensated CEO last year bringing in $2.3 billion, and just in the last three months Facebook shares have more than doubled.
And if history is any guide, the 28-year old Zuckerberg and his wife may take interest in the neighboring properties.