and finance, vol. 80, p. 2131 – 2161. tucker, p ( 2010 ), resolution of large and complex financial institutions : the big issues, available at http : / / www. bankofengland. co. uk / publications / speeches / 2010 / speech431. pdf weitzman, m l ( 1974 ), “ prices vs. quantities ”, review of economic studies, vol. 41, p. 477 – 91. annex table 1 present value of output losses ( % of 2009 gdp ) fraction of initial output loss which is permanent 25 % 50 % 100 % uk world source : bank calculations table 2 average ratings difference for a sample of banks and building societies 1. 56 1. 68 1. 63 uk global average 1. 94 2. 36 2. 21 4. 00 2. 89 3. 24 average ( 2007 – 09 ) 2. 50 2. 31 2. 36 1. all figures are year - end 2. the uk sample contains 16 banks and building societies in 2007 and 2008 and 13 in 2009. the global sample contains a sample of 26 banks across a range of sizes and countries for 2007 and 28 banks in 2008 and 2009. source : moody ’ s and bank calculations. table 3 average ratings difference for uk banks and building societies ( a ) mean max difference in sample min difference in sample large banks 2. 67 small banks 0. 14 large banks 2. 78 small banks 0. 86 large banks 4. 67 small banks 3. 43 large banks 3. 37 small banks 1. 48 category average ( 2007 – 2009 ) ( a ) the “ large ” category includes hsbc, barclays, rbs, lloyds tsb, alliance & leicester and bradford & bingley ( up to 2008 ), and nationwide. the “ small ” category includes building societies : chelsea, coventry, leeds, principality, skipton, west bromwich and yorkshire. the ratings are year - end. source : moody ’ s and bank calculations. table 4 estimated subsidy for uk banks and building societies ( £bn ) and global banks ( $ bn ) chart 1 average assets relative to gdp of us commercial banks ( a ) chart 2 concentration of the us banking system ( b ) chart 3 largest uk company ’ s assets in each sector relative to gdp

are tenuous at best, cryptocurrencies are of growing interest to policymakers, many of whom prefer to term them crypto - assets expressly because they are not true currencies — a convention i will adopt for the balance of my remarks. on the upside, as i will come onto in a moment, some of the underlying technologies are exciting. whatever the merits of cryptocurrencies as money, authorities should be careful not to stifle innovations which could in the future improve financial stability ; support more innovative, efficient and reliable payment services as well as have wider applications. on the downside, at present, crypto - assets raise a host of issues around consumer and investor protection, market integrity, money laundering, terrorism financing, tax evasion, and the circumvention of capital controls and international sanctions. the bank of england ’ s fpc is currently considering the risks posed to uk financial stability. and internationally the financial stability board ( fsb ) will report to the g20 in argentina later this month on the financial stability implications of crypto - assets. at present, in my view, crypto - assets do not appear to pose material risks to financial stability. this is in part because they are small relative to the financial system. even at their recent peak, their combined global market capitalisation was less than 1 % of global gdp. in comparison, at the height of the dotcom mania, the valuations of technology stocks were closer to about a third of global gdp. and just prior to the global financial crisis, the notional value of credit derivative swaps was 100 %. in addition, major uk financial institutions have minimal exposures to the crypto - asset ecosystem. looking ahead, financial stability risks could rise if retail participation significantly increased or linkages with the formal financial sector grew without material improvements in market integrity, anti - money laundering standards and cyber defences. innovations are reducing computational efforts to prove a transaction, such as litecoin and ethereum ’ s proposed moves to “ proof of stake ” from “ proof of work ”. all speeches are available online at www. bankofengland. co. uk / speeches authorities are rightly concerned that given their inefficiency and anonymity, one of the main reasons for their use is to shield illicit activities. this cannot be condoned. anarchy may reign on the dark web, but in the uk it ’ s just a song that your parents used to listen