In this letter, we report Eoff-versus- Vce tradeoff curves for vertical superjunction insulated-gate bipolar transistors (SJ IGBTs), exhibiting unusual inverse slopes dEoff/dVce >;0 in a transition region between purely unipolar and strongly bipolar device behaviors. This effect is due to the action of p-pillar hole current when depleting the drift layer of SJ IGBTs during turnoff and the impact of current gain on the transconductance. Such SJ IGBTs surpass by a very significant margin their superjunction MOSFET counterparts in terms of power-handling capability and on-state and turnoff losses, all at the same time.