Bankaların İş Modellerindeki Benzerliğin Sistemik Riske Etkisi: Avrupa Örneği

Abstract

Bu çalışma, Avrupa bankalarının bilançolarından türetilen üç ana unsurun sistemik risk üzerindeki etkilerini analiz etmektedir. Bu unsurlar, batmayacak kadar büyük olup olmama durumu, aktif ve pasif kalemler bazında yapılan çeşitlendirmenin düzeyleri ile iş modelinin diğer bankalarınkine benzerliğidir. Bu çerçevede araştırma, aşağıdaki temel sorulara yanıt aramaktadır: Benzerlik ve çeşitlendirme, sistemik riski nasıl etkiler ve birbirleriyle nasıl etkileşime girer? Bu ilişkiler, batmayacak kadar büyük bankalar ile diğer bankalar için nasıl farklılık gösterir? Benzerlik, çeşitlendirme ve büyüklük arasındaki etkileşimler, sistemik riski nasıl şekillendirir? 25 Avrupa ülkesinden 165 halka açık bankayı içeren panel veri seti üzerinde yapılan regresyon analizleri, bankalar arasında büyüklüğe göre yapılan sınıflandırmaların (batmayacak kadar büyük ve diğerleri) sistemik risk üzerindeki etkileşimli etkileri nasıl düzenlediğini ortaya koymaktadır. Bulgular, iş modeli benzerliğinin ve çeşitlendirme düzeylerinin tek başına etkilerinin ötesinde, bu değişkenlerin birbirleriyle ve banka büyüklüğüyle olan etkileşimlerinin sistemik risk dinamiklerini anlamada kritik rol oynadığını göstermektedir. Özellikle, batmayacak kadar büyük bankalarda benzerliğin sistemik riski artırdığı, aktif çeşitlendirmesinin azalttığı ve pasif çeşitlendirmesinin artırdığı bulunmuştur. Diğer bankalarda ise bu dinamiklerin, pasif çeşitlendirmesi hariç olmak üzere, ters yönde etkiler gösterdiği ortaya konulmuştur. Bu bağlamda, finansal istikrarın sağlanabilmesi için iş modeli benzerliği ile çeşitlendirme düzeylerinin banka büyüklüğü ve ülkeye özgü ekonomik koşullara göre optimize edilmesi gerektiği vurgulanmaktadır. Çalışma, Basel regülasyonlarının sistemik risk bağlamında daha kapsamlı bir yaklaşımla yeniden değerlendirilmesi gerektiğine işaret etmekte ve politika yapıcılar için hem mikro hem de makro düzeyde uygulanabilir öneriler sunmaktadır.

Keywords

• Sistemik risk
• benzerlik
• çeşitlendirme
• batmayacak kadar büyük
• banka regülasyonu

The Impact of Bank Business Model Similarity on Systemic Risk: The European Case

Abstract

This study analyzes the impact of three key elements derived from the balance sheets of European banks on systemic risk. These elements are the status of being too-big-to-fail or not, the levels of diversification across asset and liability items, and the similarity of a bank’s business model to those of other banks. In this context, the research seeks to address the following key questions: How do similarity and diversification influence systemic risk, and how do they interact with each other? How do these relationships differ between too-big-to-fail banks and others? How do the interactions between similarity, diversification, and size shape systemic risk? Regression analyses conducted on a panel dataset including 165 publicly traded banks from 25 European countries reveal how classifications based on bank size (too-big-to-fail and others) conditionally regulate the interactive effects on systemic risk. The findings indicate that beyond the standalone effects of business model similarity and diversification levels, their interactions with each other and with bank size play a critical role in understanding systemic risk dynamics. Specifically, it is found that for too-big-to-fail banks, similarity increases systemic risk, asset diversification decreases it, and liability diversification increases it. For other banks, these dynamics exhibit opposite effects, except for liability diversification. In this context, it is emphasized that ensuring financial stability requires optimizing business model similarity and diversification levels based on bank size and country-specific economic conditions. The study highlights the need for a more comprehensive approach to reassess Basel regulations in the context of systemic risk and offers practical recommendations for policymakers at both micro and macro levels.

Keywords

• Systemic risk
• similarity
• diversification
• too big to fail
• bank regulation

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