Prior research has found that the announcement of marketing alliances tends to produce no effect on firm value creation in a high-tech context. This article reexamines this issue and investigates whether the characteristics of a firm's network of alliances affect the firm value created from the announcement of a new marketing alliance. The authors investigate whether network centrality, network density, network efficiency, network reputation, and marketing alliance capability influence firm value creation. They examine this question using an event study of 230 announcements for marketing alliances in the software industry. The results indicate that, in general, marketing alliance announcements create value (i.e., abnormal stock returns) for the firm in the announcement period event window. Furthermore, network efficiency and network density have the strongest positive impact when they are moderate; network reputation and network centrality have no effect. These results point to the greater role of relational network characteristics than size-/status-based benefits. Finally, marketing alliance capability, which reflects a firm's ability to manage a network of previous marketing alliances, has a positive impact on value creation.