ÖZET

Since oil is one of the basic inputs in economies, changes in oil prices are important to countries, particularly oil importing countries. In this regard, this paper analyzes the causal relationship between oil prices and sector indices (BIST-Industrial, BIST-Service, BIST-Financial, and BIST-Technology) in the aftermath of the 2008 financial crisis in Turkey. First, the Johansen cointegration test is employed to analyze whether there are longrun relations between oil prices and sector indices over the period from 2008-10-2018:10. Then, the long-run relationships between oil prices and the sector indices was investigated using the Granger causality test based on the Vector Error Correction Model (VECM), and the Standard Granger test is used to analyze the causality between the variables without a long-run relationship. According to the results, there are long-run bidirectional relations between oil prices and the BIST-Industrial, the BIST-Service, and the BIST-Technology sector indices, respectively. -In the short-run period, however, there is a unidirectional relation running from oil prices to the BIST-Technology sector index. There is neither a short-run or long-run relation between oil prices and the BIST-Financial sector index.

Among the current trends of economics, the new institutional economics is gaining more and more importance. The characteristic of the new institutional economics is that it has integrated instutions into the research field of economics. With the new institutional economics, the research field of neoclassical economics has widened, and different disciplines such as law, sociology, organizational theory and political science have started to be analyzed from an economic perspective. Although the new institutional economics started to develop in the 1970s, its origins can be traced back to Coase's paper on "The Nature of the Firm". As stated by Williamson, one of the leading theorists of the new institutional economics, it continues to develop in two aspects. First, it focuses on governance structure and contributes to the development of transaction cost economics. Second, it deals with institutional environment and provides a basis for the economics of property rights. This study will discuss the ideas of Coase, known as the founder of the new instutional economics, and also the contibutions of his studies to the development of the new instutional economics.

This study examines the impacts of oil shocks on real stock returns in Turkey by using the vector autoregressive model (VAR). It analyzes over the 2008:10-2018:04 period. The logic lying behind this periodization is to analyze the impacts of oil prices on real stock returns for the 2008 post-crisis period. According to the results obtained, real stock returns have a positive and a statistically insignificant response to oil price shocks at the beginning. This is inconsistent with the expectations of economic theory. This inconsistency has several reasons, but the flow of foreign portfolio investment to developing countries may be a decisive factor after the financial crisis of 2008. This flow of foreign investment may have had an impact on stock returns in developing countries such as Turkey, especially when the interest rates were lowered to almost zero in developed countries following the financial crisis of 2008.