We use a laboratory experiment to investigate whether statements from governmental
institutions expressing concerns about price increases trigger such increases by
facilitating tacit collusion. Such statements on market conduct are disclosed after an
exogenous and unexpected upward cost shock. Two potential channels affecting tacit
collusion work through (i) a reduction of strategic uncertainty and (ii) an inducement
of correlated beliefs. We find that issued statements of concern become self-fulfilling
prophecies, triggering price increases by reducing strategic uncertainty. Our results
suggest that institutions should seriously reflect on possible adverse effects of statements
of concern when considering disclosing them.