A huge $448.52 billion of jumbo mortgages were securitized in the MBS market last year, but the biggest increase came in Alt A deals, rather than traditional jumbo securities, according to a new analysis by Inside MBS & ABS. Heady home price appreciation rates helped fuel a strong supply of new jumbo mortgages – loans that exceed the Fannie/Freddie purchase limits – in 2005. Last year’s flow of jumbo home loans into the MBS… [One data table included]