The second quarter net operating loss from our Life & Group and Corporate segments was $37 million in 2011 and $24 million in 2010. Craig will comment on these segments in a moment. The Property & Casualty Operations combined ratio was 105.7% in the second quarter of 2011 as compared to 89.5% in the same period last year. These ratios benefited from favorable development of 4.8 points and 18.4 points, respectively. Second quarter catastrophe losses represented 6.9 points in 2011 and 3.3 points in 2010. While our cat losses were significant considering the severity of the widespread events and their impact in industry loss ratios, we believe our 6.9 points of losses reflect well on our disciplined approach to catastrophe management. Before development and catastrophes, the second quarter 2011 combined ratio improved 1 point to 103.6% from 104.6%. The improvement was primarily driven by the accident year loss ratio before catastrophes. This ratio was 69.4% in the second quarter of 2011 as compared to 70.3% in the second quarter of 2010.
The Property & Casualty Operations expense ratio in this year's second quarter was 34.2%, which was inflated by a onetime charge. Our run rate expense ratio is approximately 33.5%, consistent with our full year expense ratio in 2010 at which we've been able to sustain while continuing to make investments to grow our Property & Casualty business.
Noncommissioned expenses contributed 15.1 points to the expense ratio in this year's second quarter, a 0.2 point decrease from the prior year period, while commission expenses contributed 19.1 points, an increase of 0.6 point. The Property & Casualty Operations combined ratio was 103.8% for the first 6 months of 2011 as compared to 95.8% in the same period in 2010. These ratios benefited from favorable development or 3.4 points and 10.6 points, respectively. Catastrophe losses in these periods represented 5.3 points in 2011 and 3 points in 2010.