Study: homeowners more volatile than private passenger auto

The homeowners insurance line was three times more volatile than private passenger auto during the 14-year period 1992-2005, due in large part to the active 2004 and 2005 Atlantic hurricane seasons, according to a recent study by Aon Re Global.

The study shows that the private passenger auto line experienced the lowest volatility during that period, followed by the auto physical damage, commercial auto and workers’ compensation lines. Excluding catastrophe losses, the homeowners line has a risk level comparable to the commercial auto line. Liability lines and medical malpractice also have significantly above average volatility.

Aon Re’s Insurance Risk Study quantifies the systemic risk for each line of business, representing the risk to a large portfolio from non-diversifiable risk sources such as: changes to market rate adequacy and underwriting terms and conditions; misestimating plan loss ratios; frequency and severity trends; weather-related losses; legal reforms and court decisions; level of economic activity and macroeconomic factors.

For large books of non-cat-exposed business, systemic risk is the major component of underwriting volatility.

The report examined volatility in nearly two dozen lines including commercial multi peril, other liability (occurrence and claims made), fidelity and surety, and medical malpractice.

The Insurance Risk Study applies sophisticated techniques from risk theory to a database of National Association of Commissioners’ Annual Statement data from accounting years 2001-2005 for 1,875 individual U.S. groups and companies. The database, covering all 21 Schedule P lines of business, contains more than 800,000 observations.