Intensified competition in financial markets determines the need to look for new, more competitive structure of financial intermediation. In terms of the banking sector it refers to banks' specialisation in various market segments, its natural consequence being that banks get motivation to build close relationships with their customers. Relationship banking is about permanent mutual commitment of a bank and its customer to build a long-term relationship based on financing.

Access to customer data is a basic problem of financial intermediaries. Benefits of customer data are one of the principle determinants of banks' profitability. That is why they are particularly prone to change in the sector, resulting from competition in the market. However, competition limits the bank's possibility of benefiting from information acquired within relations with a financed company. Financial intermediaries compete one with another in collecting data on their existing and potential customers. In response to the collected data banks offer differentiated financial services and products; due to specialisation in a given segment, they acquire expert knowledge about the customer.

The author attempts to answer the questions of whether close relations with customers allow banks to effectively monitor their situation in order to prevent loss of invested funds, and how the informational asymmetry, specialisation and competition within relationship banking tend to influence the quality of corporate order in the banking sector.

The analysis of literature indicates that relationship banking allows banks to tailor their offering to the type of customers, their financial standing, as well as their requirements, needs and expectations. The process of collecting customer data generates considerable costs, which grow in line with clients' variety and heterogeneity. That is why in peripheral segments banks tend to resign from investing in the development of specialisation, confining their commitment to the necessary minimum, or compensate for incurred costs by higher fees, commissions or interest rates. In this area customer differentiation, and so the differentiation of data collected from them, favours more intensive competition.

Relationship banking affects the efficiency of allocation of funds and contributes to the creation of added value. Within the developed relations it also eases the informational asymmetry and reduces agency costs. Data acquired within the relations allows banks to provide long-term, renewable loan facilities to their corporate customers. Lasting and close relations of a bank with financed companies may facilitate their monitoring and may constitute an integral part of the bank's system of control over management in those companies. Easing problems which usually accompany separation of the management from the ownership, relationship banking provides for the achievement of goals of corporate governance.