Vera Guerin, whose late father Nathan Shapell survived two Nazi concentration camps and became one of California’s largest property developers, emerged as a billionaire last week after Toll Brothers Inc. agreed to buy her family’s Shapell Industries Inc.’s homebuilding business for $1.6 billion.

Toll, the largest U.S. luxury-home builder, will pay cash for Beverly Hills-based Shapell, the companies said in a Nov. 6 statement. The deal will more than double the number of California lots controlled by Toll to about 9,200, with most in coastal markets where vacant land is hard to come by.

“The Shapell company has a long, storied history,” Douglas Yearley Jr., chief executive officer of Toll Brothers, said in a telephone interview. “Nathan Shapell, his brother David and their brother-in-law Max Webb from the ’50s on tied up ranches in the best locations in northern and southern California and got those ranches entitled. It’s a perfect fit for Toll Brothers.”

Founded in 1955, Shapell has developed about 70,000 homes and 7,000 apartments in California, and manages more than 2.7 million square feet of shopping centers, offices and other commercial property, according to a Toll investor presentation. Shapell’s homebuilding division had revenue of $274 million in the first 8 months of 2013.

Hidden Billionaire

Shapell’s Porter Ranch development, with 1,786 remaining home sites, is the largest planned community in the city of Los Angeles, and its Gale Ranch in San Ramon, east of San Francisco, has 1,538 more lots to build on. Shapell sold 347 homes this year through August for an average of $791,000.

Guerin, 66, inherited her father’s 43 percent stake in the company prior to his 2007 death, according to a person familiar with Shapell’s ownership who asked not to be identified because the information is private. The Toll deal will give her about $690 million before taxes. After the transaction, Shapell will still own 10,000 apartments, according to the person. It also owns five shopping centers and four office buildings, according to its website.

The apartments are worth $1.5 billion, or about $150,000 per unit, and the offices and shopping centers are valued at about $210 million, according to a real estate broker familiar with the company who asked not to be identified because he’s close to one of Shapell’s principal owners. Her stake in those assets is worth about $735 million, giving Guerin a net worth of at least $1.3 billion, according to the Bloomberg Billionaires Index.

Auschwitz, Buchenwald

Guerin’s fortune may be bigger, based on a 2004 loan document filed by JPMorgan Chase Commercial Mortgage Securities Corp., which said she owned more than 10 million square feet of offices, “several thousand” apartments, and “several million” square feet of retail space through partnerships. Shapell’s company website only lists holdings of 113,500 square feet of offices, and shopping centers totaling 629,000 square feet.