We enrich Milgrom and Roberts' (1982) limit-pricing model to allow an incumbent to signal his costs with both price and advertisements. Our fundamental result is that a cost-reducing distortion occurs, in that the incumbent behaves as if there were complete information but his costs were lower than they are. Preentry price is therefore distorted downward, and demand-enhancing advertising is distorted upward, as a consequence of signalling. If advertising is a purely dissipative signal, it is not used, nor therefore distorted. Recent refinements of the sequential equilibrium concept are featured.