19 : can negative supply shocks cause demand shortages? ”, nber working paper series, no 26918. [ 16 ] see, for example, the strand of literature attempting to evaluate the effects of fiscal stimuli during the covid - 19 crisis : bayer, c., born, b., luetticke, r. and muller, g. ( 2020 ), “ the coronavirus stimulus package : how large is the transfer multiplier? ”, cepr discussion papers, no 14600, centre for economic policy research ; hinterland, n., moyen, s., roehe, o. and staehler, n. ( 2020 ), “ gauging the effects of the german covid - 19 fiscal stimulus package ”, mimeo ; and pfeiffer, p., werner, r. and in ’ t veld, j. ( 2020 ), “ the covid19 - pandemic in the eu : macroeconomic transmission & economic policy response ”, discussion paper 127, european commission. [ 17 ] see also lane, p. r. ( 2020 ), “ the pandemic emergency : the three challenges for the ecb ”, speech at the jackson hole economic policy symposium, federal reserve bank of kansas city, 27 august ; and lane, p. r. ( 2020 ), “ the ecb ’ s monetary policy in the pandemic : meeting the challenge ”, speech at the 62nd nabe annual meeting, 6 october. https : / / www. ecb. europa. eu / press / key / date / 2020 / html / ecb. sp201126 ~ c5c1036327. en. html 19 / 19

cleared markets face. on the other hand, some consequences of central clearing may increase systemic risk : • as a result of growing risk concentration in ccps and in a limited number of large global dealers, which act as general clearing members as a gateway for other financial institutions to ccps, • as a consequence of mutualisation, risks may spread among participants and markets more widely and the distribution of losses is more difficult to predict, • in order to avoid mandatory clearing, we might see migration of risk outside of the regulated universe through the artificial creation of bespoke ( and hence risky ) products that are not suitable for central clearing. moreover, the systemic effect of clearing depends on whether risk is redistributed to those who are more able to deal with it, which is difficult to determine. finally, the overall systemic effect depends on the incentives for risk - taking and central clearing that accompany risk redistribution. [ slide 5 ] to promote central clearing and avoid regulatory arbitrage, a number of reforms have been adopted including : ( i ) mandatory clearing, ( ii ) margin requirements for non - centrally cleared trades, and ( iii ) higher capital requirements for non - centrally cleared trades. this highlights the crucial complementarity between the regulation of banks and the regulation of financial market infrastructures ( fmis ), with the overall objective that regulation reduces overall risk, and does not shift it around the financial system. cooperation between the committee on payments and settlement systems and the international organisation of securities commissions ( cpss - iosco ) on the one hand, and the basel committee on banking supervision ( bcbs ) on the other hand, is key in this respect. a macroeconomic impact assessment led by the bis focused on the effects of these reforms and found net benefits of 0. 12 % of gdp per year. these are estimates of the long - run consequences of the reforms and are expected to apply once those reforms have been fully implemented and produced their full economic effects. however, central clearing also involves risk redistribution and potentially the creation of new risks. the overall impact is therefore less certain : there are significant benefits which need to be balanced against potential new risks and uncertain risk redistribution effects. ultimately, it seems to me that the success of central clearing as a tool for promoting financial stability critically depends on two factors : ( i ) the ability of ccps to handle the risks they are concentrating and thus the design of their corporate governance, risk management and recovery frameworks and ( ii ) the ability of the