The metal-insulator transition in a strong magnetic field is analyzed for a model composed of three electron groups and one hole group, corresponding to the energy spectrum of bismuth in a magnetic field oriented along the principal axis. Two possible types of carrier pairing are found: (a) electrons with holes, and (b) electrons with electrons within a single group. Both are pairings of the insulator type. Nevertheless, free carriers remain in the metal, even in the “insulator” state. The thermodynamic properties, dielectric constant at T=0, and conductivity as a function of the temperature are investigated. The absence of superthermal conductivity is demonstrated.