The underwriting results in the current quarter reflected a GAAP combined ratio of 105.4 percent, as compared to 95.9 percent in the prior year quarter. This increase of 9.5 points in the combined ratio resulted from higher catastrophe losses (16.9 points), partially offset by higher underlying underwriting margins (5.7 points) and higher net favorable prior year reserve development (1.7 points). Catastrophe losses in the current quarter were mostly due to Storm Sandy. Net favorable prior year reserve development in the current quarter occurred in all three business segments.
The current quarter underlying GAAP combined ratio was 90.7 percent (which excludes net favorable prior year reserve development and catastrophe losses) as compared to 96.4 percent in the prior year quarter. This improvement of 5.7 points primarily resulted from lower non-weather related property losses in Personal Insurance and earned rate increases exceeding loss cost trends in all three business segments.
Total revenues of $6.477 billion in the current quarter increased 2 percent from the prior year quarter. Within total revenues, net investment income of $689 million increased $37 million from the prior year quarter due to private equity performance in the non-fixed income portfolio, partially offset by a slight reduction in fixed income returns due to lower reinvestment rates.
Net written premiums of $5.385 billion in the current quarter increased 2 percent from the prior year quarter. Renewal rate gains continued across all segments. Retention rates remained strong across all three business segments and were generally consistent with recent quarters. New business volumes in Business Insurance increased slightly from the prior year quarter but decreased in Financial, Professional & International Insurance and Personal Insurance. Net written premiums in Business Insurance also benefited from continued positive exposure change at renewal, as well as a modestly higher level of positive audit premiums compared to the prior year quarter.