  We consider a minimal model where the Higgs boson arises as an elementary
pseudo-Nambu-Goldstone boson. The model is based on an extended scalar sector
with global SO(5)/SO(4) symmetry. To achieve the correct electroweak symmetry
breaking pattern, the model is augmented either with an explicit symmetry
breaking term or an extra singlet scalar field. We consider separately both of
these possibili- ties. We fit the model with the known particle spectrum at the
electroweak scale and extrapolate to high energies using renormalization group.
We find that the model can remain stable and perturbative up to the Planck
scale provided that the heavy beyond Standard Model scalar states have masses
in a narrow interval around 3 TeV.
