Dimensionless efficiency η as a function of BH spin a for different models. The radiative efficiency η _NT for the NT disk is shown as the blue-dashed–dotted line, and the EM outflow efficiency ﹩{\eta }_{\mathrm{EM}}={P}_{\mathrm{EM}}/\dot{m}{c}^{2}﹩ at the event horizon is shown with dark blue dots. We provide separate fits to η _EM(a) dependence for positive (pink) and negative (orange) spins (see Equation 16). A rapidly spinning BH fed by an MAD can achieve EM energy outflow efficiencies >100%. These fits form the inputs to our semi-analytic MAD spin-down model.