Issuance of new structured mortgage securities backed by agency pass-throughs boomed during the second quarter, according to a new analysis and ranking by Inside MBS & ABS. A total of $86.17 billion of agency-backed REMICs were issued during the second quarter, up 34.4 percent from the first three months of the year. That brought year-to-date issuance in the sector to $152.01 billion, an increase of 6.4 percent from the same period in 2005. … [One data table included]