3 Recent Disruptions and Potential Reforms in the U.S. Treasury Market: A Staff Progress Report, Inter-Agency  Working Group for Treasury Market Surveillance, November 8, 2021. 4/4  BIS central bankers' speeches
In the financial sector the new fintech companies are challenging the traditional banking business models and providing services in all functions of finance, from payment systems, to saving, borrowing, managing risks and financial advice. This has important implications for productivity and competitiveness and for further deepening the interconnectedness of the global economy. II. Central banks have reacted to the global financial crisis in three main ways:   Highly expansionary and unconventional monetary policy. Central banks were already applying near-zero interest rates in 2008. But interest rate policy was not effective under the “zero-lower bound”, which is basically the Keynesian liquidity trap at near-zero interest rates. Accordingly, it was necessary to develop new policy instruments, the so-called “unconventional monetary policy”, mainly quantitative easing and forward guidance. The result has been a huge increase in central bank balance sheets. In terms of GDP, the approximate size of the balance sheet of the central banks before the crisis was 12% in the Eurosystem, 5% in the US and 20% in Japan. These numbers have increased between four and five times,  3/6  and are now at around 40% in the Eurosystem, around 4.4 trillion euro, 24% in the US (4.4 trillion US dollars), and almost 100% of GDP in Japan (5.2 trillion Yen).  Tighter financial regulation and supervision. Pre-crisis regulation was based on microprudential regulation and supervision. The crisis revealed this framework to be no longer effective to ensure financial stability in the new context of globalised and highly interconnected financial markets.