Some researches indicate that vertical integration is a strategy that is best pursued at the mature stage of the market (or certain product). At earlier stages it can really reduce profits. It is open to question that it also diverts attention from the actual business of the organization. Suppliers seldom excel in retail operations and, theoretically, retailers should focus on their sales outlets rather than on manufacturing amenities (Marks & Spencer, for example, very intentionally provides significant amounts of technical assistance to its suppliers, but does not have them).