Originations of non-agency jumbo mortgages through three quarters in 2012 increased by 23.3 percent compared with the same period in 2011. While 12 non-agency jumbo mortgage-backed securities have been issued this year, jumbo originations are largely being held in portfolio by banks competing for high-quality borrowers. An estimated $148.0 billion in non-agency jumbos were originated through the first nine months of 2012, including an estimated $52.0 billion in ... [Includes one data chart]