The global financial crisis highlighted that the size of some financial institutions was too big compared to the real economy, or they had too many connections with important counterparties. Because of this, any problems that affect these institutions can have fatal results on the whole financial system and the real economy. For this reason, governments spared no effort in saving these institutions. There are several global examples where governments or central banks give guarantees, inject capital, lend funding, or support the acquisition of their most important financial institutions (for example, Northern Rock, AIG, or Bear Stearns).

Without these steps, the chance for a collapse seemed to be too high, which would have been accompanied with extreme high costs because of bailouts. All in all, identification of systemically important financial institutions again became a hot topic. One of the main lessons of the crisis was that the biggest and most interconnected...