Health insurers battered by rising costs and employer benefits cuts caught a break when Minneapolis-based managed-care provider UnitedHealth Group saw its stock jump nearly 8%, despite reporting a sharp drop in second-quarter profit. UnitedHealth shares rose $2.38, or 10%, to $26.21 from Monday's closing price of $23.83, as the prices of other publicly traded insurers like Aetna Inc. and WellPoint Inc. also jumped several percentage points.