What is Derivative Suit?

Legal Definition
A shareholder derivative suit is a lawsuit brought by a shareholder on behalf of a corporation against a third party. Often, the third party is an insider of the corporation, such as an executive officer or director. Shareholder derivative suits are unique because under traditional corporate law, management is responsible for bringing and defending the corporation against suit. Shareholder derivative suits permit a shareholder to initiate a suit when management has failed to do so. Because derivative suits vary the traditional roles of management and shareholders, many jurisdictions have implemented various procedural requirements to derivative suits.
-- Wikipedia