low - yield environment therefore played a key role in the accumulation of fragilities that led to the crisis. its core macroeconomic precondition was a global glut in net savings as well as liquidity, coupled with a lack of safe financial assets at global level. the savings and liquidity glut was largely the outcome of policies that reinforced or insufficiently countered the effects of savings - investments and current account configurations. part of the responsibility for the creation of global imbalances lay with those countries that underestimated the risks of high consumer indebtedness and large current account deficits. however, export - led growth strategies pursued by several systemically important emerging market economies, including china, also contributed substantially to the build - up of fragilities at global level. these strategies, intentionally or not, led to persistent interventions in the foreign exchange market on a unilateral basis and the accumulation of large external reserves reinvested in the borrowing countries. in the short term, the strategies generated growth in these economies ; however they had several negative effects, both at domestic and at global level. domestically, they led to forms of financial underdevelopment that had negative consequences on capital allocation and income distribution. at global level, exportled growth strategies made it easy for the us to incur large and increasing current account deficits and to delay the necessary adjustments. they also gave rise to an accumulation of dollar - denominated assets which could not be reinvested in emerging market economies due to their financial underdevelopment in the form of a shortage of safe financial assets. moreover, the build - up of these assets resulted in a de facto taxation of consumption and a subsidy for inefficient investment, which in turn prevented an efficient inter - temporal smoothing of consumption and a rebalancing of growth towards domestic demand. all of these factors contributed to the compression of yields across the maturity spectrum. according to the average estimates of a pool of studies, central bank purchases of us treasuries alone lowered us long - term interest rates by around 70 basis points, with some studies estimating an impact of up to 200 basis points. weak surveillance mechanisms surveillance mechanisms with “ put your house in order ” at their heart proved to be weak in the run - up to the crisis. the imf recognised that a surveillance framework centred around “ put your house in order ” was insufficient to meet the demands of the world economy in 2007, when it updated

yen projection bis central bankers ’ speeches ( chart 9 ) balance sheet projections tril. yen end - 2012 end - 2013 end - 2014 ( actual ) ( projected ) ( projected ) monetary base jgbs cp 2. 1 2. 2 2. 2 corporate bonds 2. 9 3. 2 3. 2 exchange - traded funds ( etfs ) 1. 5 2. 5 3. 5 japan real investment ( j - reits ) estate trusts 0. 11 0. 14 0. 17 loan program support 3. 3 banknotes current deposits breakdown of the bank's balance sheet total assets others ) total liabilities ( including and assets ( including others ) net bis central bankers ’ speeches ( chart10 ) transmission channels quantitative easing : expansion in the monetary base qualitative easing : expansion in jgbs and risk assets increase in jgb purchases and their maturity extension purchases of etfs and j - reits channel downward pressure on the entire yield curve channel lowering risk premia of asset prices channel portfolio adjustments by banks and investors channel inflation expectations improvement of financial conditions （ borrowing costs, bank credit, stock prices, etc. ） increase in expenditure ( consumption, fixed investment, exports ) improvement of the output gap decrease in real interest rates increase in inflation expectations increase in the cpi bis central bankers ’ speeches