This paper is aimed at the analysis of the insulated base MOS-controlled thyristor (IBMCT) using numerical simulations. This power device is composed of a vertical thyristor structure, two MOS gates (on-gate and off-gate) and a floating ohmic contact (FOC). Transient simulations confirm the turn-off capability, and show that holes are diverted from the p-base to the FOC during the turn-off process. The electrical characteristics have been compared with those of the shorted anode IBMCT. It is pointed out that this last structure is significantly faster than the IBMCT because the shorted anode provides a direct path for the extraction of the electron charge excess existing in the drift region during the turn-off process.