Appetite for jumbo mortgages among big banks has limited issuance of non-agency jumbo mortgage-backed securities in recent months. And analysts suggest that the next increase in the guaranty fees charged by the government-sponsored enterprises could shift even more production to bank portfolios instead of into non-agency MBS. Certain big banks continue to offer interest rates on jumbos that are below rates on comparable mortgages with conforming balances. For a 30-year fixed-rate non-agency jumbo with ...