There are multiple definitions - click on the translation that matches your context.

actio pro socio

Substantiv

full

actio pro socio

Comparative law notes

Germany

Under the common law, this phrase refers to an action brought by one partner against his co-partners to compel them to carry out the terms of the partnership agreement. Since the traditional German definition of this same phrase is identical - i.e., meaning that one or more owner/partner/shareholder enforces a claim against his co-owner/co-partner/co-shareholder(s) - one can use the phrase as a full matching "translation".