Khalid Abdullah El Shalash and Yussif Abdullah El Shalash each hold significant stakes — 9.1 and 7.7 percent, respectively — in Dar Al Arkan Real Estate Development Co , one of the largest property firms in the Kingdom. With those holdings worth more than $750m, even a conservative count of the family fortune clips the $900m barrier, although the holdings are likely to suffer if the regional real estate slump continues for too much longer.