Marketing management involves choosing target markets that not only get new customers but also retain the existing ones. It is a business subject, which is based on research and study of practical applications of marketing techniques and management of the marketing resources. The one who excels in this field is known as marketing manager. The job of the marketing manager is to influence the timing and level of customer demand so as to help the sales. It actually depends on the size of the business and environment in the corporate industry. Like if he is working in a huge production company, he will be the general manager of a particular product category assigned to him and he will be responsible for profit and loss with respect to the product. And in small business there is no marketing manager as his job is taken over by the partners of the company.