Natural disasters are taking a toll on Progressive insurance's bottom line and led to huge losses

REUTERS/Therese Apel The insurance industry's basic business model hinges on the idea that, over the long run, insurers can be profitable if they are smart about the policies they underwrite. For Progressive, profiting from solid underwriting practices has been a big part of its success, yet weather always plays a factor in determining short-term results. Coming into Thursday's third-quarter financial report, Progressive investors expected that the insurer had suffered from worse conditions dur...