NEW YORK — Mortgage analysts said homeowners and the problems they are having making their monthly mortgage payments, combined with an undervaluing of the risks in securities backed by mortgages, are at the root of the current financial upheaval.

In interviews with financial media outlets, the analysts made a distinction between the previous mortgage industry, which saw the majority of mortgages held by the institutions that underwrote them, and the current mortgage market which sees mortgages bought and sold freely and then bundled into vehicles that can be used to back securities which can be bought and sold.

Underpinning the free sale of mortgages and the issuing of securities is the underlying belief that homeowners would keep their mortgage loans sound. When sufficient numbers of home owners stopped being able to do that, cracks appeared in the foundation of the mortgage market overall, the analysts explained.