With securitization volume reaching new record levels in the booming subprime and Alternative A markets in the first half of 2005, most top mortgage lenders are funneling a substantial volume of new production into the non-agency MBS market. A new analysis by Inside Mortgage Finance of mortgage securitization patterns among 10 top loan originators shows that a hefty 42.9 percent of their combined MBS production was executed in the non-agency MBS market. … [One data table included]