Strategic alliances are the primary collaboration form for organizations participating in value webs, the most widely used form of structuring business activities in the digital economy. Such alliances can assume many alternative governance modes, ranging from hierarchy-like alliances (joint ventures) to market-like alliances (contractual agreements). This paper proposes a conceptual model of factors affecting managers? preferences for an alliance governance mode. The model integrates a set of influencing factors that concern the organization, the environment in which it operates, as well as its compatibility with the alliance partner(s). The model also incorporates a new determinant, called Expected Alliance Value, which denotes the value that a firm expects to receive from its alliance with a value web partner.