Sam Altman's Mansion Was Once the Most Expensive Home Listing in San Francisco. A New Lawsuit Says It's a 'Lemon.'

In 2020, OpenAI CEO Sam Altman bought the then-priciest home listing in San Francisco for $27 million. Four years later, a lawsuit alleges that the 9,500-square-foot property was a poorly constructed "lemon," including mold issues and a leaky infinity pool that flooded the lower level.

Greg Malin, CEO of home developer Troon Pacific, took viewers on a tour of the 950 Lombard St. property in a May 2020 Architectural Digest video , showing off everything from the estate's "Batcave" garage to its wellness cottage.

The video listed the estate for $40.5 million, the most expensive at the time, though Altman would later buy it for about $27 million. The estate takes up an entire city block — the same size as six, normal-sized lots. The main house has five bedrooms and six-and-a-half baths, and the cottage has a sauna, steam room, massage area, and spa.

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A lawsuit filed last week in San Francisco Superior Court, which The San Francisco Standard connected to Altman on Tuesday as the home's owner, details how the luxurious residence fell apart after a few years of use. The filing accuses Troon Pacific and Malin of "shoddy construction" and "corner cutting" at the 950 Lombard St. estate.

The construction flaws "were concealed and/or not subject to discovery by reasonable investigation," the filing reads.

The lawsuit alleges a lower-level flood caused part of the ceiling to fall. The source of the damage? The leaking infinity pool. The lower level of the mansion also had "widespread" mold. Correcting these issues alone would cost more than $4 million, the plaintiffs estimate.

There were also contractor bags pushed into sewer lines and one unconnected line that deposited raw sewage on the ground at the side of the property, according to the lawsuit.

Troon Pacific has been called out before for "fraudulent" behavior. In May, the developer had to pay back $48.1 million to investors who backed a home renovation project that was never completed.

Altman is listed as the current owner of 950 Lombard St., per The San Francisco Standard, and is worth at least $2 billion, according to the Bloomberg Billionaires Index .

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