Policy-makers in the US are "a long way" from being able to use macro-prudential tools successfully, New York Fed president William Dudley warned last week – speaking at a Boston Fed conference that highlighted how much uncertainty persists in this nascent policy field.

Dudley raised concerns over the lack of a "well-defined framework" for identifying imbalances and selecting the right macro-prudential tool in response, as well as the "fragmented" regulatory structure in the US.

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