The volume of new mortgage securities issued during the third quarter remained at historically high levels but was off slightly from the previous quarter, according a new analysis based on the Inside Mortgage Finance MBS Database. A total of $514.93 billion of mortgage-backed securities were issued during the third quarter, down 0.8 percent from the previous three-month period. That dropped year-to-date issuance 2.8 percent below the pace set during the first nine months of 2005... [Includes 2 charts]