Which brings me to my last point. III. Big data raise issues that cannot be solved in a national context but require a public  global reflection. Very large worldwide corporates are hugely leveraging on Big Data. Public authorities have to forge answers to concerns that may arise on an international level. Which themes should be addressed? I would like to propose a few leads. 4 1)  Data sharing has to be developed on a worldwide basis, as rightly underlined  by the IMF in the ‘Data Gaps Initiative’ that has been launched by the G20. In Europe, existing legal provisions that authorize data sharing between supervisors and central bankers could become more prescriptive and be more largely implemented in practice in all countries concerned. Data sharing between tax authorities and other public administrations should be facilitated, subject to the respect of individual privacy of course. 2)  Private innovation is fostering growth and is increasing economic efficiency. It  should therefore not be discouraged by disenabling regulations. At the same time, it would be beneficial to the economy in the long run, and to financial stability more specifically, that the global actors that handle enormous volumes of data on physical persons as well as on private entities, comply with 3 core principles: security, transparency, accountability. In a fully interconnected world, it cannot be effectively addressed at the country level. I therefore believe that it would be useful for the International Organizations to carry out a reflection and issue recommendations in this regard.
•  What about the more difficult question of whether monetary policy should be used to lean against the wind. The answer is a more obfuscating “that depends.” Specifically, it depends on the efficiency and efficacy of the macroprudential tools and institutional framework available, a point eloquently made by my colleague Don Kohn recently (Kohn 2015). •  Take the extreme case in which there are no macroprudential tools. In such circumstances monetary policy may be the only means of tackling system-wide financial risks, but it would come at the cost of significant effects on the real economy – precisely because monetary policy “gets in all the cracks.” For example, some empirical work by former Deputy Governor Charlie Bean suggests that setting Bank Rate around 200 basis points higher than it was over the over the period 2003–2006 would have reduced the growth in the ratio of household debt to GDP by just 2 percentage points from 2003–2007 at a cost of GDP growth over this period being 2.6 percentage points lower (Bean et al 2010). •  By contrast, the targeted nature of the tools available to the Financial Policy Committee under the current institutional framework in the UK makes them a natural first line of defence for dealing with build-ups in financial system vulnerability while minimising the knock-on effects to the rest of the economy – as was recognised in the financial stability knockout built into the MPC’s forward guidance.