The performance of tunneling magnetoresistive (TuMR) heads under electrical overstress and electrostatic discharge is investigated. Alumina-based TuMR longitudinal heads of the 3.5in. 160Gbytes∕platter class are subjected to controlled stress until a predefined level of relative resistance drop (5%–60%) is achieved. The bias current is then readjusted to achieve a constant bias voltage and dynamic-electric test is performed. It is found that the stressed heads still perform similarly to the unstressed ones up to a resistance drop of ∼30%. Accelerated lifetime test did not detect statistically significant differences in reliability between the stressed and unstressed parts.