When firms launch a new product into the marketplace they often aim to find a balance between building scale and provoking extensive and quick competitive reactions. Competitors react to new products when they perceive the product introduction as hostile, committed or when they feel that the product entry will have a large impact on their profitability. The present study develops a framework that shows how strong and fast incumbents react to perceived market signals resulting from a new product's launch decisions (broad targeting, penetration pricing, advertising intensity and product advantage). The strength of the relationships between the launch decisions and the perceived market signals was expected to depend on one industry characteristic (i.e., market growth) and on one entrant characteristic (i.e., aggressive reputation). We distinguished three market signals in our framework: hostility, commitment and consequences. Signal hostility refers to the extent to which the approach used by an acting firm to introduce the new product is perceived hostile whereas the commitment signal refers to the extent to which incumbents perceive the entrant firm to be committed to the new product introduction. The consequence signal is defined as the incumbents' perception of the impact of a new product entry on their profitability. We tested our framework using cross-sectional data provided by 73 managers in The Netherlands who recently reacted to a new product entry. The results clearly reveal which launch decisions create which market signals. For example, incumbents consider high advantage new products hostile and consequential. Penetration pricing and an intense advertising campaign are also considered hostile, especially in fast growing markets. Broad targeting is not perceived hostile, especially not when used by entrants with an aggressive reputation. In addition, this study explored the impact of three perceived market signals on the strength and speed of competitive reaction. The results reveal that perceived signals of hostility and commitment positively impact the strength of reaction, whereas the perceived consequence signal positively impacts the speed of reaction. The article concludes with the implications of our study for managers and academics. The relevance to managers was assessed from both the perspective of the incumbent firm that must defend, and that of the rival firm that is introducing the new product.