JPMorgan Chase is set to issue a unique jumbo MBS, its second of the year, that will include originations from 20 different lenders that far outweigh the company’s contributions to the deal. Another bank, EverBank, this week took steps to issue its second jumbo deal of 2013 as well. Since 2008, big banks have largely held their non-agency jumbo originations in portfolio, seeing better execution than non-agency MBS issuance. However, strong demand from non-agency MBS investors and a desire to shrink mortgage exposure has prompted Chase to resume issuing jumbo MBS. Chase declined...