Contemporary valuation models reject the traditional models and accept the investor as an irrational being based on past experience and behave according to their feelings, emotions and beliefs. Precisely because of the limited availability of information and the limitation of the human mind mistakes in making investment decisions are inevitable. The definition of a petty investor is actually a definition of investment sentiment that shows that it is impossible to make quite rational decisions because it is difficult to control all the factors affecting the investor. This implies the importance of investor sentiment has on investors and their decisions, and consequently the entire banking system. The 2008 global financial crisis has led to a major breakdown and falling stock levels both in the banking sector and in the entire market, and it was necessary to implement new measures in the financial market. The new regulatory framework, ie the capital requirements, were of great importance to banks in order to strengthen their solvency to economic shocks and improve their risk management. As for the shares in the banking sector as well as the shares of the rest of the market, during the financial crisis, they all experienced a drastic decline, but after new regulatory measures were implemented, and after alignment with the new capital requirements, most banks managed to recover or at least achieve a growth trend while only a few still feel the consequences of the crisis. Although the stock market index shows a much larger and faster recovery than the share of the banking sector, this difference is largely diminishing.