Abstract: Strategic alliance is the equilibrium of participators' decisions and their interactions on the efficient level of specialization and the pattern of production,and its stability boundary reflects the critical conditions converting among internal production,specialization of production and exchange in spot market or in alliances. An inframarginal analysis model of decision-making on specialization levels and production patterns illustrates the stability boundary of strategic alliances,and reveals the importance of assets and efficiency of transaction for alliances stabilities.

Key words: strategic alliances, assets value, transaction efficiency, stability boundary