Taming Bubbles for Financial Stability

金融危机已经催生了自己的一轮行话术语，但论讨厌程度和重要性，很少有能比得上“宏观金融监管”(macroprudential supervision)的。所有人一致同意，单个银行就算谨慎行事，加在一起仍有可能促成系统性风险。但金融监管机构如何缓解这种情况，甚至能否设计出缓解的工具，这一切都还不得而知。Bloomberg News英国央行行长默文•金针对这个问题存在两种看法。大部分决策者希望通过新的资本规定将宏观监管工具嵌入体系之中。当前的体系往往会鼓励银行在繁荣时期极大扩张，而更高的资产价格更高的流动性和下滑的风险认知会鼓励高风险行为。但以英国央行行长默文•金(Mervyn King)为首的一些人要求可自由选择的工具，允许监管机构在发现泡沫存在时釜底抽薪。这可能意味着实施更高的资本要求或是对金融机构的放贷加以其他限制。这两种方法都有问题，国际清算银行(Bank for International Settlements)的博里奥(Claudio Borio)最近的一篇论文就指出了这一点。要实施这些规则，监管机构就需要能够察觉整个金融体系风险的模型，而不光是银行的风险。这些模型需要具备足够的复杂性，才能确定不同资产类别以及对手方之间的联系，同时还要估算经济繁荣转为萧条的可能性。毋庸赘言，这样的模型和制造这类工具所需的数据都不存在。仅仅关注市场价格是没用的。毕竟，在经济繁荣的年代，在全世界迈向危险边缘的同时，信贷市场价格和波动减少所显示的却是全球风险正在下降。但依靠判断力的工具会带来更大的问题。决策者们真的愿意做出与市场相反的判断吗？如果英国央行本世纪初做出努力，给房市降温，本轮危机会有什么不同吗？毕竟英国房价迄今仅下跌了14%，对英国银行体系还无以构成许多人所担忧的系统性威胁。此外，决策者们将需要众多人手去观察泡沫情况，对美国房市科技类股以及新兴市场货币等林林总总的资产进行分析。而这将需要全球合作。但即使能开发出这样的宏观金融监管工具，它们可能也不足以防止将来的不稳定性。正如加拿大央行行长卡尼(Mark Carney)上个月强调的，货币政策必须分担一部分。这就意味着要调整央行的通胀目标，将资产价格以及价格稳定与财政稳定间的平衡考虑进来。对于金和贝南克(Ben Bernanke)等传统上注重通胀的央行行长来说，这种情况可能十分讨厌。但这可能是唯一一个能够发挥作用的办法。SIMON NIXON


The financial crisis has spawned its fair share of jargon, but few expressions as ugly and as important as 'macroprudential supervision.' Everyone agrees individual banks can act prudently yet collectively contribute to systemic risks. But how regulators should mitigate this, or if tools can even be devised to do it, remains far from clear.There are two schools of thought. Most policy makers would like macroprudential tools embedded into the system via new capital rules. The current system tends to encourage banks to become most extended as a boom peaks -- and higher asset prices, higher liquidity and falling risk perceptions encourage riskier behavior.But some, most vocally Bank of England governor Mervyn King, have demanded discretionary tools, allowing regulators to remove the punch bowl when they see a bubble. That could mean imposing higher capital requirements or placing other restrictions on the lending of institutions.Both approaches have problems, as a recent paper by Claudio Borio of the Bank for International Settlements acknowledges. To embed the rules, regulators will need models capable of identifying risks across the financial system, not just in banks. And those models would need to be sophisticated enough to map the linkages between different asset classes and counterparties, while also calculating the likelihood of a boom turning to bust.Needless to say, neither the models nor the data required to make these tools exist. Simply focusing on market prices won't work. After all, during the boom years, credit-market prices and reduced volatility signaled that global risks were actually falling as the world headed to the brink.But tools that rely on discretion pose even bigger challenges. Will policy makers really be willing to pit their judgment against the markets? Would it have made much difference to the crisis if the BOE had tried to cool the U.K. housing market earlier in the decade? After all, U.K. house prices have so far fallen only 14%, hardly the systemic threat to the U.K. banking system that many feared.What's more, policy makers would need teams of bubble-spotters analyzing asset classes as diverse as U.S. housing, tech stocks and emerging-market currencies. And that would need global coordination.But even if such macroprudential tools can be developed, they aren't likely to be enough to prevent future instability. Monetary policy must share the load, as Bank of Canada governor Mark Carney noted last month. That will mean adapting central-bank inflation targets to take account of asset prices and balance the demands of price stability and financial stability. That may be anathema to traditional inflation-focused central bankers such as Mr. King and Ben Bernanke. But it may be the one tool that really works.SIMON NIXON