Commercial bank holdings of mortgage securities declined again in the third quarter of 2004 but remained at the high end of their historic range, according to a new Inside MBS & ABS analysis. Banks reported a total of $829.85 billion of residential mortgage securities in their portfolios at the end of the third quarter, down 2.8 percent from the $854.12 billion they held at the midway point in 2004. Commercial bank MBS investment hit an