Financial frictions in macroeconomics

I review two examples that show how the nature of the financial system can play a central role in shaping the behavior of the aggregate economy. In the first example, variations over time in the cross-sectional dispersion of a productivity shock, which would have no aggre-gate effect in a frictionless model, produce effects that look like business cycles because of the nature of financial (and nominal) frictions. The second example suggests how a shock originating outside the financial system, which ordinarily might not be expected to have a large aggregate effect, can lead to a systemic banking collapse. The relevance of the exam-ples to the US economy is discussed.(c) 2021 Elsevier Ltd. All rights reserved.