U.S. life insurers have little exposure to collateralized debt obligations but more to other types of securities backed by residential mortgages and other assets.

Dimitris Karapiperis, a research analyst at the Securities Valuation Office, New York, a securities rating arm of the National Association of Insurance Commissioners, Kansas City, Mo., writes about insurers’ mortgage investments in the November issue of the SVO Research Quarterly.

U.S. life insurers ended 2006 with $16 billion in collateralized debt obligations and about $652 billion in all structured products other than CDOs, Karapiperis writes in the article.

Investments in structured products other than CDOs accounted for about 30% of the life insurers’ bond portfolios, Karapiperis reports.

At the end of 2006, about $38 billion, or 5.8%, of the U.S. life insurers’ bond holdings were in products backed by sub-prime loans, Karapiperis writes.

Only about $661 million in U.S. life company holdings were in CDOs backed by sub-prime loans, according to Karapiperis.

About $36 billion of the life companies’ sub-prime investments were in securities that ended 2006 with ratings of A or higher, and about $24 billion was in securities with ratings of AAA, Karapiperis writes.