Cross-selling is the action or practice of selling among or between clients, markets, traders, etc. or the action or practice of selling an additional product or service to an existing customer. This article deals exclusively with the latter meaning. In practice, businesses define cross-selling in many different ways. Elements that might influence the definition might include the size of the business, the industry sector it operates within and the financial motivations of those required to define the term.The objectives of cross-selling can be either to increase the income derived from the client or clients or to protect the relationship with the client or clients.