The financial crises of the last twenty years brought new economic concepts into classrooms discussions. This article introduces undergraduate students and teachers to seven of these models: (i) misallocation of capital inflows, (ii) modern and shadow banks, (iii) strategic complementarities and amplification, (iv) debt contracts and the distinction between solvency and liquidity, (v) the diabolic loop, (vi) regional flights to safety, and (vii) unconventional monetary policy. We apply each of them to provide a full account of the euro crisis of 2010-12.

This chapter surveys the literature on bubbles, financial crises, and systemic risk. The first part of the chapter provides a brief historical account of bubbles and financial crisis. The second part of the chapter gives a structured overview of the literature on financial bubbles. The third part of the chapter discusses the literatures on financial crises and systemic risk, with particular emphasis on amplification and propagation mechanisms during financial crises, and the measurement of systemic risk. Finally, we point toward some questions for future research.

Liquidity and deflationary spirals self-generate endogenous risk and redistribute wealth. Monetary policy can mitigate these effects and help rebalance wealth after an adverse shock, thereby reducing endogenous risk, stabilizing the economy, and stimulating growth. The redistributive channel differs from the classic Keynesian interest rate channel in models with price stickiness. Central banks assume and redistribute tail risk when purchasing assets or relaxing their collateral requirements. Monetary policy (rules) can be seen as a social insurance scheme for an economy beset by financial frictions. As with any insurance, it carries the cost of moral hazard. Redistributive monetary policy should be strictly limited to undoing the redistribution caused by the amplification effects and by moral hazard considerations.

This paper summarizes and explains the main events of the liquidity and credit crunch in 2007-08. Starting with the trends leading up to the crisis, I explain how these events unfolded and how four different amplification mechanisms magnified losses in the mortgage market into large dislocations and turmoil in financial markets.