Higgs-like spectator field as the origin of structure.

We show that the observed primordial perturbations can be entirely sourced by a light spectator scalar field with a quartic potential, akin to the Higgs boson. The framework relies on the indirect modulation of reheating, which is implemented without any direct coupling between the spectator field and the inflaton and does not require non-renormalisable interactions. The scenario gives rise to local non-Gaussianity with $f_{\rm NL}\simeq 5$ as the typical signal and it can be realised for the Higgs boson in the Standard Model extended with right-handed neutrinos. However, the Standard Model running should be modified for the setup to produce the observed perturbation.