In this paper the authors study a supply chain with two suppliers and a customer who offers a new product. Suppliers can accept or reject the new product offer according to its profitability and have to decide on their base stock levels. In a competitive setting, supplier 1 acts as a Stackelberg leader and two schemes are considered: supplier 1 gets the demand ratio he wishes to be allocated and the remaining quantity ratio is allocated to supplier 2; in a second scheme, supplier 1 decides to respond to the entire demand and to subcontract a part of it to supplier 2. Both situations are investigated analytically and numerically, and conditions that allow supplier 1 to select the best scheme are provided. Then, the cooperative setting is considered: it is supposed that the suppliers cooperate by sharing the resulting profit among them according to the equal allocation policy. It is proved that both suppliers improve their profits in this case. Some numerical examples are illustrated.