  Status of quantum wavefunction is one of the most debated issues in quantum
foundations -- whether it corresponds directly to the reality or just
represents knowledge or information about some aspect of reality. In this
letter we propose a {\it $\psi$-ontology} theorem that excludes a class of
ontological explanations where quantum wavefunction is treated as mere
information. Our result, unlike the acclaimed Pusey-Barrett-Rudolph's theorem,
does not presume the absence of holistic ontological properties for product
quantum preparations. At the core of our derivation we utilize the seminal
no-go result by John S. Bell that rules out any local realistic world view for
quantum theory. We show that the observed phenomenon of quantum nonlocality
cannot be incorporated in a class of $\psi$-epistemic models. Using the well
known Clauser-Horne-Shimony-Holt inequality we obtain a threshold bound on the
degree of epistemicity above which the ontological models are not compatible
with quantum statistics.
