Tangible assets are characterized by being easily identified and cataloged, it will be because his own nature that will prevent them from contributing fully to creating and sustaining competitive advantage. On the other hand, intangible resources it can contribute most to sustaining competitive advantage and therefore business success. Amit and Schoemaker (1993) state that strategic assets are a subset of the resources of the company, but especially of capabilities. Thus, the competitive advantages a company will be based essentially on the knowledge and skills they possess, as well as management systems to control, ie, the competitiveness will be held mainly in shaping its portfolio of intangible assets. Others also feel that the powers of a portfolio company composes the origins of competitive advantage. Being able to identify three characteristics of core competencies:
1) provide access to a wide variety of markets, 2) significant increase of product value for end users, and 3) unique harmonization of technologies and production skills which will be difficult to imitate. From this point of view, the company will not be only one set of businesses, with varying degrees of relationship, but is designed as a set of skills and competencies may be applied to various fields of activity, ie, a series of activities linked by a common technological trunk. This will reach some sort of generic technology that will allow its application to different types of products. These skills and competencies will be developed over time and also will be improved with use, unlike other resources which also owns the company and its physical and financial loses importance and the business portfolio concept in front of the portfolio of skills . Adam Portnoy pursues this goal as well.