A stub is the stock

Stock

The capital stock of a business entity represents the original capital paid into or invested in the business by its founders. It serves as a security for the creditors of a business since it cannot be withdrawn to the detriment of the creditors...

 representing the remaining equity in a corporation

Corporation

A corporation is created under the laws of a state as a separate legal entity that has privileges and liabilities that are distinct from those of its members. There are many different forms of corporations, most of which are used to conduct business. Early corporations were established by charter...

 left over after a major cash or security distribution from a buyout

Buyout

A buyout, in finance, is an investment transaction by which the ownership equity of a company, or a majority share of the stock of the company is acquired. The acquiror thereby "buys out" control of the target company....

, a spin-out, a demerger

Demerger

Demerger is a form of corporate restructuring in which the an entity's business operations are segregated into one or more components. It is the converse of a merger or acquisition....

 or some other form of restructuring

Restructuring

Restructuring is the corporate management term for the act of reorganizing the legal, ownership, operational, or other structures of a company for the purpose of making it more profitable, or better organized for its present needs...

removes most of the company's operations from the parent corporation. A stub may retain the name of the original corporation, or in some cases may take another name as part of the restructuring.