A robust $75.23 billion of Alternative A MBS were issued during the first quarter of 2006, up 26.3 percent from the same period last year, according to a new ranking and analysis based on theInside Mortgage Finance MBS Database. Although it was up from year-ago levels, Alt A MBS issuance in the three months of the year was down 13.5 percent from the fourth quarter, and it marked the lowest volume since the beginning of… [One data table included]