A review of statutory underwriting results for the top 10 writers of commercial auto insurance reveals that those with the highest growth rates over the last five years also had the best combined ratios, with one exception.

A handful of individual companies continue to post strong underwriting profits in commercial auto despite more challenging industry conditions. Among the largest commercial auto writers, Berkshire Hathaway Inc. has posted the best underwriting performance over the last five years, followed by Progressive Corp. and Old Republic International Corp.

Berkshire Hathaway has experienced the strongest growth in primary commercial auto market activity over the last five years through expansion of its Homestate Cos. organization. The company is anticipated to further grow in commercial auto given expansion plans in the excess and surplus lines market.

Underwriters with significant commercial auto underwriting losses in recent years, including American International Group Inc., Hartford Financial Services Group and Liberty Mutual Group, have reduced their premium exposures in the segment over the last several years.

Nationwide Mutual Group is one exception to this practice as the company has expanded its premium volume by 50 percent in the last five years, attributable in part to acquisitions, despite generating significant underwriting losses.

The top 10 list was compiled based on 2013 net written premiums for the commercial auto line. The chart below shows how they ranked and market shares for each of the 10 groups.

For a more detailed discussion of trends in the workers compensation line for the industry overall, see related article, “Commercial Auto Insurers Still Struggling.”