It is proved that the S matrix element S(λ, k) for the z-4 repulsive potential → 1 as |λ|→∞ in the sector 0 ≤| argλ | <π/2-ε and that it has infinitely many Reggepoles in a small angle neighbourhood of the imaginary axis with their real and imaginary parts approaching ∞ simultaneously. Ordinary double dispersion relation does not hold in this case.